In recognition of Earth Day on April 22, 2013, the USGS is highlighting a few aspects of climate change. The effects of climate change have been documented in the United States and around the world. These effects pose challenges and risks to our landscapes, natural and agricultural resources, wildlife, the economy, and the public health and safety of our communities.

USGS scientists seek to measure, document, and understand the changes that have occurred in the Earth’s recent and distant past, and then interpret and communicate the causes and consequences of those changes.

USGS expertise is diverse, for example, seeking to improve our understanding of climate change effects on wildlife and ecosystems; risks to coastal communities associated with sea-level rise, coastal erosion, and storms; how carbon circulates across the globe, including how and where it can be stored in ecosystems and subsurface rocks; and changes in water resource availability, including the effects of droughts and floods.

The USGS makes data free and easily accessible to the public, resource managers, policymakers and other decisionmakers. As the nation’s earth-science agency, the USGS provides unbiased scientific information that serves as a foundation for sound decisions as we face these climate change challenges.

Learn more about USGS climate change science and expertise by visiting the USGS Climate and Land Use Change website.

Slideshow: Faces of Climate Change

The following slideshow highlights examples of climate change impacts to variety of places and people across the globe. This aims to give a glimpse of the many faces of climate change.

Video Series: America’s Climate Change Questions

America has questions about climate change, and the USGS is providing answers through a video series called, Climate Connections.

In these videos, USGS scientists are engaging in conversations and addressing questions from across the nation. The USGS has authoritative and science-based information to address a wide range of topics related to climate change.

There are six episodes from Colorado, the District of Columbia, Glacier National Park, Puerto Rico, and North and South Carolina.

Hyperlinks and details to each episode are provided below.

Watch the Videos

Questions from Colorado include:

• How is Colorado affected by climate change and how can I learn more?
• Were the wildfires this past summer related to climate change?
• Do the bark beetles infesting trees have anything to do with climate change?
• How does the ocean change the climate, and vice versa?

Questions from high school students in D.C. include:

• If you could tell the public one thing about climate change, what would it be?
• Does climate change impact humans or animals more?
• How will climate change affect D.C.?
• When did climate change begin?

Questions from Glacier National Park include:

• When I come back in ten years, what will I see in Glacier National Park?
• How is climate change impacting the glaciers?
• Does all the snow we received this winter help the glaciers?
• How do receding glaciers and climate change affect the local economy in terms of recreation, agriculture, tourism?

Questions from Puerto Rico include:

• Why has the rainy season been so long in Puerto Rico?
• How is global warming impacting the island of Puerto Rico?
• What are solar storms and are they related to climate change?
• Will we see polar bears on the island of Puerto Rico?

Questions from North and South Carolina include:

• How does climate change affect the coast and where can I learn more?
• What are scientists currently doing in regards to rivers and streams?
• Does planting trees impact climate change?
• What do we know now that we didn’t know in the 1970s?

Questions from students in North Carolina include:

• Do all scientists agree that climate change is occurring?
• Could climate change impact fishing?
• Will the climate change abruptly or slowly over time?
• What is geothermal energy and how does it impact the climate?

Observing phenology is a fun activity for adults and children alike.

Nature’s Notebook  invites citizens to get outside this spring, and join their neighbors in observing plant and animal life events in your backyard.

Gardeners, farmers, birders, hikers, anglers, joggers or all-around nature enthusiasts are already recording the recurring events they see in the lives of the plants and animals around them,  such as when cherry trees or lilacs blossom, when robins build their nests, when salmon swim upstream to spawn, or when leaves turn color in the fall.

Each entry in Nature’s Notebook represents important scientific information about an actual event in a plant or animal’s life.  And when amassed together, these observations are making it possible for scientists to better understand how species are responding to climate change and to develop more informed tools for responding to climate change.

This spring, we hope citizen-scientists will help us out in one (or several!) of Nature’s Notebook new campaigns: Cloned Lilacs and Dogwoods; Maples, Oaks, and Poplars; PopClock; New England Leaf-Out Project; the Juniper Pollen Project; and the Common Lilacs and Native Flowering Dogwood Project. Visit the campaigns pages to learn about which species are of interest for your area.

But if these campaigns don’t interest you, there are many other types of species Nature’s Notebook welcomes observations for – including plants, birds, mammals, insects, fish, reptiles and amphibians.

Spring Springing Earlier?

Scientists recently used data collected by observers in Nature’s Notebook to determine that the “green-wave” of spring – or the flush of growth on trees and other plants across the nation – has already shifted – and will shift more dramatically in the future – as the climate changes.  The study (published in Geophysical Research Letters) showed how the green-wave, which now takes about 75 days to travel from Miami to Maine, may take as few as 59 days by the end of the century!  Thus, spring will arrive more quickly, and forest areas may become more similar to one another along the Eastern Seaboard.

And, in fact, warm spring temperatures in both 2010 and 2012 in the eastern half of the country resulted in record early activity of plant and animals – 2-3 weeks early in some places and for some species; the data for spring 2013 – which officially starts today – are rolling in, but they suggest early activity among some plants and animals this year as well.

Citizen-scientists monitor the different life events of certain animals and plants, including the bluebell flower pictured here.

Jake Weltzin, an ecologist with USGS and the executive director of the USA National Phenology Network, which manages the Nature’s Notebook observing program, noted that although an earlier spring brings early birds and beautiful flowers and glorious days at the shore, it also brings us earlier-arriving allergies and pests like ticks and mosquitoes. And while a longer growing season can result in increased yields for some crops, it is risky because of the higher likelihood of plant damage due to late frosts or later onset of drought. For example, in spring 2012, fruit and vegetable crops in portions of the Midwest were damaged from a very early spring followed by frosts.

Phenology, the Study of Nature’s Calendar

The study of when recurring seasonal life stages of plants and animals occur is called phenology, and people have tracked phenology for centuries for the most practical of reasons: when to hunt and fish, when to plant and harvest crops, and when to move livestock or animal herds.

Tracking phenology is just as critical today for the same reasons and for new ones too.  Not only are the data in Nature’s Notebook helping researchers understand how plants and animals are responding to climate change, but also how those responses are affecting people and ecological systems. This information is already being used in ways that benefit society, including developing more accurate indicators of spring, forecasting the onset of allergy season or the chances of western wildfires, managing wildlife and invasive plants, and helping in habitat-restoration efforts.

Arizona saquaro will be one of the species looked at by USA-NPN volunteers.

Is Climate Change Knocking Nature Out of Sync?

Changes in phenology are among the most sensitive biological indicators of local, regional and global change. Just as in the United States, many springtime events around the world are occurring earlier — and fall events happening later — than in the past. These changes are happening quickly for some species and more slowly, or not at all, for others, altering relationships and processes that may have been essentially stable for thousands of years.

Some wildlife – like caribou and butterflies and hummingbirds – are becoming mismatched from their plant food resources, which are responding differently.  Migrations for some birds are changing too, as they can now overwinter instead of moving south for the winter, or as they fly north, adjusting their pace to keep up with an advancing front of spring flowering.

Phenology, Pollinators, and Food

Working farms and ranches need phenology information too:  pollination by native insects contributes more than $3 billion in agricultural crops each year. Climate-driven changes in the phenology of crops and native insects could change the effectiveness of insect pollination for better or for worse, and certainly complicates management decisions.  However, because little is known about how pollinator phenology is changing, it is difficult to accurately assess how crops will be affected and how farmers might best adapt. By collecting observations of insect phenology and crop phenology together, the USA-NPN is contributing to our understanding of the changes taking place and helping to ensure the viability of crops across the country.

Where You Come In

In three simple steps, you can become a citizen scientist: 1. Join Nature’s Notebook, 2. Choose the location and species you’ll observe, and 3. Start observing!

By joining the program, you ultimately empower your hobby to benefit scientific discovery.

USA-National Phenology Network citizen-scientist Lucille Tower records the one millionth observation on maple vine in the large nature database.

What Changes Are Happening Where I Live?

Want to know more about observed changes in plant and animal phenology in your region over the last century? Explore the USA-NPN’s recent series of regional information sheets:

• Alaska and the Arctic
• Great Plains
• Hawai’i and the Pacific Islands
• Midwest
• Northeast
• Pacific Northwest
• Southeast
• Southwest

More about the USA-NPN

The USA National Phenology Network is a partnership among governmental and nongovernmental science and resource management agencies and organizations, the academic community and the public.  There are more ways to get involved – partner your organization with the Network, let us know about legacy phenology data sets or even share a dataset you may have already collected, or help us rescue historical bird migration datasets.  For more information visit USA-NPN or contact Jake Weltzin at jweltzin@usgs.gov.

Listen to a Spanish-language podcast about USA-NPN.

Photograph of Sólheimajökull outlet glacier in Iceland. More information can be found on page 118 of this new publication. This includes a more detailed graphic of fluctuations in temperature and how that corresponded to glacier advance/retreat.

Water, the key to life, is also a key to understanding the way the natural world works. Water in the form of ice is especially instructive.

Water moves through the hydrologic cycle, one of the most basic and vital processes of Earth’s systems, in three forms — as a liquid in seas and streams; as a vapor in clouds and fog; and as a solid in ice. Found predominately in glaciers, the world’s ice is, by nature, temperature dependent. Thus the presence or absence of glaciers and their geographic distribution around the globe are closely linked to Earth’s historical and current climate conditions and to changes in global sea level.

The recently published State of the Earth’s Cryosphere at the Beginning of the 21st Century summarizes past and present-day changes in the Earth’s cryosphere (the whole of its frozen water) and describes the ongoing and potential effects of those changes. Extensively illustrated in print and connected to a companion online image gallery, this volume supplies a synthesis for 10 other geographically-based volumes in the 11-volume Satellite Image Atlas of Glaciers of the World.

“Evidence from a wide range of satellite and field observations over the last 30 years shows that nearly all glaciers, snowpack, sea ice, and permafrost are in retreat around the globe,” said USGS Director Marcia McNutt. “That this worldwide phenomenon can be readily observed by a non-specialist without any sophisticated data processing or image enhancement is strong evidence that our rapidly warming planet is causing major changes in one of the key Earth systems.”

Glaciers as Climate Indicators

Glaciers cover about 15.9 million square kilometers of Earth’s land surface (2009 figures), slightly less than the size of Russia. Ice sheets in Antarctica and in Greenland store most of the glacier ice on Earth, occupying 95.5 percent of glacier area and containing 99.4 percent of glacier volume. Other glaciers are located on all of Earth’s continents except Australia. (The term glacier in the Satellite Image Atlas includes ice sheets, a long-held definition also used by the Scott Polar Research Institute and the American Geosciences Institute.)

Glaciers have waxed and waned throughout the history of Earth in response to several factors: the global climate, the latitudinal position of the continents, the geographic position and elevation of mountain ranges, and slight changes in the Earth’s orbit. Presently, glaciers around the world are responding to natural warming after the end of the Little Ice Age in the late 1800s, as well as to the warming that human activity has caused through increased concentrations of carbon dioxide and other greenhouse gases in the atmosphere.

For example, since the late 19th century, all of Iceland’s glaciers have decreased in area and thickness. Although Iceland’s glaciers retreated from 1930 through 1970, they advanced during 1970 to 1995. Since 1995, however, the decrease has been quite dramatic. If the climate continues to warm, glaciers in Iceland will probably decrease by 40 percent during the 21st century and will virtually disappear by 2200.

The overwhelming scientific consensus is that burning of fossil fuels and deforestation, both of which are human activities, are critical factors in the Earth’s observed warming.

Landsat image of the largest ice cap in Europe, the Vatnajökull ice cap. More information and this image can be found on page 91 of the new publication.

Melting Glaciers ­— Rising Seas

Water covers 70 percent of the Earth’s surface. Of all the world’s water, water in the oceans makes up 97 percent while frozen water in glaciers accounts for just 2 percent.

Although 2 percent seems like a small ratio, it is the long-term exchange between glacier ice and the oceans that principally determines global sea level. Warming of the Earth alters the relationship between global sea level and the volume of glacier ice on land, as frozen water is converted to meltwater and transferred from land to the oceans. The warming of the Earth’s oceans also serves to increase the volume of the water and add to global sea rise.

In response to variations in the volume of glacier ice on the continents, sea level has repeatedly fallen and risen between glacial and interglacial periods of Earth’s geologic history. Approximately 20,000 years ago, for example, sea level was about 125 meters (410 feet) lower than at present (2009 figures). If all of the present glacier ice on land were to melt, sea level would rise an additional 75 meters (246 feet).

The present rate of the global rise in sea level is now about 3-4 mm each year, equivalent to a stack of three to four U.S. pennies.

The Cryosphere: Beyond Glaciers

The cryosphere (from Greek, cryos, “cold”) is the term that describes the portions of the Earth’s surface where water is in solid form. It includes glaciers, snow cover, floating ice, and permafrost, although glaciers are the dominant component.

Global snow cover is measured on a daily basis, and snow-cover trends can be measured over decades. These advances have important applications to hydrological forecasting, enabling us to predict flooding and water supply.

Sea ice covers vast areas of the polar oceans, affecting the atmosphere, the oceans, and terrestrial and marine ecosystems of the polar regions. Changes in the ice, if sufficiently large, can initiate regional and global climatological and ecological consequences. This publication notes that 2007 was a record low year for Arctic sea ice extent, but an even lower minimum was recorded more recently in September 2012.

Permafrost or perennially frozen ground includes northern peatlands and frozen, organic-rich sediments that contain large amounts of carbon. Deep, perennially frozen sediments, both onshore and beneath the Arctic shelves, contain methane hydrates. These carbon-rich deposits are potential sources of greenhouse gases, especially methane, if climate warming continues.

The Cryosphere in Education

A substantial section of the new volume is designed for use by teachers and students in the classroom to improve the understanding of major aspects of global environmental change. The print version of this section contains a wall-size plate, “Earth’s Dynamic Cryosphere,” and eight Supplemental Cryosphere Notes (two-page summaries of topics included in the report). These materials support a major national effort to increase higher-education student enrollment in the Earth sciences.

Global Collaboration and Space-Based Views

Image of the Greenland ice sheet. More information and this image can be found on page 89 of the new publication.

The State of the Earth’s Cryosphere represents an extensive collaboration among 20 glaciologists from the United States and three other nations (Canada, Denmark, and Norway) who represent 14 scientific institutions. Since 1988, more than 110 scientists from 24 countries have contributed to the 11-volume series, Satellite Image Atlas of Glaciers of the World (USGS Professional Paper 1386A-K).

The goal of Satellite Image Atlas of Glaciers is to establish a comprehensive baseline of glacier conditions on all continents so that subsequent change can be readily seen and investigated. The advent of spaced-based Earth observation satellites — beginning with the first Landsat satellite in 1972 and continuing with the forthcoming launch of Landsat 8 — made that sweeping objective feasible.

Full Citation

Williams, R.S., Jr., and Ferrigno, J.G., 2012, State of the Earth’s Cryosphere at the Beginning of the 21st Century: Glaciers, Global Snow Cover, Floating Ice, and Permafrost and Periglacial Environments: U.S. Geological Survey Professional Paper 1386-A, 496 p. (with a Plate of the “Earth’s Dynamic Cryosphere,” and a set of eight “Supplemental Cryosphere Notes” about the “Earth’s Dynamic Cryosphere and the Earth System”).

Learn More

Image gallery for State of the Cryosphere

Other volumes of Satellite Image Atlas of Glaciers of the World

Landsat Image Mosaic of Antarctica (LIMA)

Coastal-Change and Glaciological Maps of Antarctica (I-Map 2600 series)

Modeling forecasts consistently have demonstrated that the geographic ranges of Rocky Mountain trout species will shrink by some 20 to 90 percent over the next 50 to 100 years as climate change accelerates in the region. Predicted water temperature increases in high-elevation rivers and streams, coupled with reduced water flows, are certain to add to existing stresses for Rocky Mountain trout.

What Models Cannot Do

A native bull trout swims in the cool waters of the Flathead River near Glacier National Park, Montana. The tail end of a native Westslope cutthroat trout can be seen below.

The models themselves, however, don’t provide the regional or local information that resource managers need to take action now to offset the negative effects of climate change on the diversity and abundance of trout species in an individual watershed.

Consequently, USGS researchers and their colleagues at the U.S. Forest Service and Colorado State University wanted to see if closely examining existing and past land-use and habitat changes in five key Rocky Mountain river basins could help provide the kind of detailed, geographically specific information that resource managers need. Over the past century, intensive land use and development have altered some of these aquatic systems, with cascading effects on ecosystems and popular trout fisheries.

The importance of the study’s findings, published in the scientific journal Fisheries, stems from the fact that the analyses did not include predictions into the future, but were driven by real observations across the western United States.  The analyses are the result of actual data across some of the coldest regions of the lower 48; they give a glimpse of what is likely to occur in the future.

Under a rapidly changing climate of the Rocky Mountains, the authors wrote, many trout populations and species will be able to adapt, but others, overwhelmed by future changes, will not survive.

“It’s not enough to know that significant habitat reductions are expected to occur for native trout of the Rocky Mountains over the next 50 to 100 years,” said Clint Muhlfeld, a USGS scientist and co-author on the paper.  “To help native trout species survive into the future, managers need solid scientific information to take decisive action now.”

River Basins and Trout in the West Already Impacted by Climate Change

The researchers assessed five river systems of the Rocky Mountain west where native trout and climate have been documented: the Flathead River Basin in northwest Montana and southeast British Columbia, the Boise River Basin in central Idaho, the Green River Basin in western Wyoming, the Rio Grande Headwaters Basin in southern Colorado, and the rivers and streams of the Greater Yellowstone Ecosystem in Montana and Wyoming.

Because climate change has been ongoing for multiple decades, although at a slower pace than forecasted for the future, the study showed that it is already possible in many instances to see the early indications of stream ecosystem responses to climate change and to use that information to make decisions about the future. It also demonstrated that the importance of different kinds of stressors varies from basin to basin and depends on local factors.

“Most exciting, however, is that the study clearly illustrates that real data are available now that can be used to understand the local effects of climate change and how those changes threaten native trout populations,” Muhlfeld said. “With that information, managers can take science-based actions that can be refined as more information becomes available through time.”

Warmer Temperatures, Earlier Snowmelt, and Reduced Summer Flows the New Norm

On Iceberg Lake in Glacier National Park, ice from the glacier is breaking up and melting at a rapid rate. Cold, glacier fed waters provide crucial habitat for native aquatic species such as trout, and as the ice is disappearing, so are the ideal habitats to sustain native ecosystems.

The researchers found that the average annual air temperature had increased across all five of these basins over the last 60 years, that spring snowmelt runoff is also occurring sooner, that streamflows in summer are lower, and that winter flooding is increasing in some areas.  All of these findings, said Muhlfeld, have important implications for the future of Rocky Mountain trout fisheries.

In fact, noted Muhlfeld, Rocky Mountain trout populations in all of the river basins they studied are already exhibiting signs of stress, such as having to migrate farther upstream to find more suitable habitat, competing with invasive species for habitat and food, and hybridizing with some invasive fish species. Other stresses include a greater risk of eggs being washed away from increases in winter flooding, increased wildfire risks in streamside ecosystems, and reduced summer habitat due to lower flows.

Fishing as Part of the National Heritage Affected

“Fishing in our national parks and charismatic streams such as the Yellowstone River is part of our heritage,” added Robert Al-Chokhachy, another USGS scientist who co-authored the paper. “The  increase in angling closures over the past decade due to the effects of higher temperatures and reduced streamflows also illustrates how climate shifts are likely to have profound socio-economic impacts,” Al-Chokhachy added.

Where to Go From Here

The authors emphasized that it is still early enough that fast-acting, proactive management decisions over the next few decades will minimize losses of these economically and ecologically important trout populations during this transitional century.

“The challenge now is to identify what actions are possible to mitigate the effects of climate change in order to provide these fishes with an opportunity to adapt,” Al-Chokhachy said.

This study was funded by the USGS National Climate Change and Wildlife Science Center, which is helping meet the challenges of climate change and its effects on fish, wildlife and their habitats.

For More Information:

Climate Change and Native Salmonids Collaborative Research Site

Native Fishes of the Northern Rockies

Climate Change in Mountain Ecosystems

(Videocast) Climate Connections: Questions from Glacier National Park, MT

USGS researcher Craig Allen stands on the edge of Mesa Alta, amid diverse forest and woodland in the uplands of northern New Mexico; note some recently dead ponderosa pine and Douglas-fir in the field of view. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire.

For hundreds of years, forests of piñon pine, ponderosa pine and fir trees have covered millions of acres of mesas, plateaus and mountains in the semi-arid southwestern United States. Like forests everywhere, they provide food and shelter for countless species and help anchor vital watersheds and soils of the region.

But their days may be numbered. Based on a new study co-authored by the USGS, projected climate change impacts suggest a grim picture for current forests in the U.S. Southwest.

Research led by A. Park Williams of the Department of Energy’s Los Alamos National Laboratory came to this conclusion by comparing the tree-ring record to climate data collected in the Southwest since the late 1800s. The researchers aligned some 13,000 tree-core samples with known temperature and moisture data, further blending in known historical events such as documented megadroughts that drove the ancient Pueblo Indians out of longtime settlements such as Mesa Verde, Colorado.

Worst Forest Drought Stress in 400 Years

What they found was this: since 2000, southwestern U.S. forests have experienced more drought stress than during any other period in more than 400 years. What’s interesting about this is that precipitation totals since 2000 haven’t been exceptionally low, but temperatures have been exceptionally high. These high temperatures have caused the atmosphere’s ability to evaporate water from soil and plants also to be exceptionally high.

Think of the atmosphere as a water-thirsty sponge: the warmer the air, the thirstier the sponge.  When the summers are too hot and dry, the trees lose much of the water that they otherwise would have used for growth. If this happens too often, trees become stressed and more vulnerable to disturbances like forest fires and bark beetle infestations.

Forest Growth Rates Predictable Using Climate Records            

When Williams and the other researchers, including USGS scientist and study co-author Craig D. Allen, compared southwestern tree-ring records to climate records, they found that southwestern forest growth rates can be predicted very effectively using just two climate variables: winter precipitation and summer-fall atmospheric evaporative demand.

The researchers were able to predict future forest growth rates using these climate and tree-growth relationships, combined with projections of future climate trends. The results: all climate models project warming to cause large increases in summer-fall atmospheric evaporative demand (thirstier sponge). No models project large increases in winter precipitation. If the climate models are correct, forest growth will decrease substantially in the coming decades primarily due to increasing drought stress from warmer growing season temperatures.

Tree Rings Link Past and Current Drought Stress

Drought and beetle-killed piñon pines in Walnut Canyon National Monument near Flagstaff, Arizona, amid a few surviving trees. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire.

The tree-ring records in the Southwest extend back in time for more than 1,000 years. This allowed the researchers to investigate how future forest drought-stress likely will compare to periods of major drought stress in the past. The tree-ring records indicate that two “megadrought” events, during the 1200s and again in the 1500s, occurred in the past 1,000 years. Past research has shown that both of these events probably coincided with widespread forest die-off in the Southwest. So, the researchers treat forest growth rates during those extreme megadroughts as a benchmark for drought conditions strong enough to cause widespread forest die-off. If warming occurs as rapidly as projected by climate models, forest drought-stress conditions are likely to exceed those historic megadrought conditions on a regular basis by the 2050s. In fact, the study forecasted that during the second half of this century, about 80 percent of years are projected to exceed those megadrought levels.

Williams says the current drought event, which began in 2000, demonstrates how close southwestern forests already may be to reaching drought-stress levels unprecedented in at least a millennium. The team concluded that forest drought stress during 4 of the past 13 years (about 30 percent), including 2011 and 2012, matched or exceeded megadrought-type levels. The only other 13-year periods when megadrought-type conditions were reached with such frequencies in the past 1,000 years were during the megadroughts themselves.

What’s Going to Happen to Southwestern Forests in the Future?

Sunset as seen through the smoke of a prescribed burn in the Jemez Mountains, New Mexico. The burn was conducted to restore fire as an ecosystem process and reduce hazardous tree densities and fuel loads due to more than 100 years of fire suppression. Foreground trees (Douglas-fir and aspen) were killed during the Cerro Grande fire in 2000. Forest drought stress is strongly correlated with tree mortality from poor growth, bark beetle outbreaks, and high-severity fire.

As trees become more stressed from increasingly hot, dry summers, eventually they will not be able to continue to grow in their current locations, and fires and beetle infestations will take an increasing toll. We can expect to see increased numbers of trees dying, with many not being replaced. Eventually, if warming trends continue as projected by state-of-the-art climate models, the current forests will give way to ecosystems more tolerant of prolonged, severe drought. This would mean substantial changes in forest species composition to more drought-tolerant trees, or even forest-replacing shrublands and grasslands.

The article, “Temperature as a potent driver of regional forest drought stress and tree mortality,” appears in the October 2012 Nature Climate Change. Authors are A. Park Williams (LANL), Craig D. Allen (U.S. Geological Survey), Alison K. Macalady (University of Arizona), Daniel Griffin (University of Arizona), Connie A. Woodhouse (University of Arizona), David M. Meko (University of Arizona), Thomas W. Swetnam (University of Arizona), Sara A. Rauscher (LANL), Richard Seager (Columbia University), Henri D. Grissino-Mayer (University of Tennessee), Jeffrey S. Dean (University of Arizona), Edward R. Cook (Columbia University), Chandana Gangodagamage (LANL), Michael Cai (LANL), Nate G. McDowell (LANL).

For More Information:

• Seeing the Forest and the Trees: USGS Scientist Links Local Changes to Global Scale

• Craig D. Allen Staff Page

• Western Mountain Initiative: Effects of Climate and Global Change on Western Mountains

• Climate Change: The Science of Impacts

Enjoying Father's Day at Kenai National Wildlife Refuge. Photo by Karen Laubenstein, USFWS.

More than 10,000 visitors to the country’s National Wildlife Refuge System say they are happy with their experiences on National Wildlife Refuges, according to just-published results from a survey by the U.S. Geological Survey. This is good news for the U.S. Fish and Wildlife Service, which manages the diverse network of refuges.

Some 90 percent of visitors to National Wildlife Refuges who were surveyed indicate they are satisfied with each of four key refuge offerings: services provided by employees or volunteers, recreational opportunities, refuge information and education, and the refuge’s job of conserving fish, wildlife and their habitats.

The Refuge System attracts nearly 45 million visitors annually. Of this total, 25 million people per year observe and photograph wildlife, more than 9 million hunt and fish, and more than 10 million participate in educational and interpretation programs. The System, considered the leading network of protected lands and waters in the world dedicated to the conservation of fish, wildlife, and the associated habitat, comprises 556 national wildlife refuges and 38 wetland management districts throughout the United States and its territories, encompassing a total of more than 150 million acres.

One of the goals of the Refuge System is “to foster understanding and instill appreciation of fish, wildlife, and plants, and their conservation.” Refuges do this by providing the public with accessible places to view, hunt or otherwise enjoy wildlife and the outdoors. Understanding the perceptions of visitors and the quality and character of their experiences on refuges is a critical element of managing these lands and meeting the goals of the Refuge System.

Surveying visitors at William L. Finley National Wildlife Refuge near Corvallis, Ore. Photo by George Gentry, FWS

To this end, the U.S. Fish and Wildlife Service worked with social science experts at the USGS to conduct a scientific, independent national survey of refuge visitors to better understand visitor needs and experiences. The information will help the Service manage visitation to the refuges and design programs and facilities that respond to visitor needs while conserving wildlife.

The survey was conducted during 2010 and 2011 at 53 refuges across the country by refuge personnel, volunteers and Refuge “Friends” group members using a standardized survey instrument. The results provide a summary of visitor and trip characteristics, visitor opinions about refuges and their offerings, and visitor opinions about alternative transportation and climate change. In addition to overall satisfaction with refuge services and experiences noted above, the survey results revealed that:

• More than half of visitors had been to multiple national wildlife refuges in the past year.
• More than half of visitors were non-local, living more than 50 miles from the refuge they visited.
• Non-local visitors stayed in the local community for an average of 4 days, and the refuge was the primary destination of the trip for many of them.
• During visitors’ most recent trip to the refuge, the three primary activities were wildlife observation, birdwatching and fishing.

The survey also asked visitors their opinions about climate change. Most visitors indicated they are personally concerned about the effects of climate change on fish, wildlife and habitats. Just over half of visitors agreed they take actions to alleviate those effects and feel they stay well-informed about the issue. Most visitors agreed that future generations will benefit if climate change effects on fish, wildlife and habitats are addressed. They also agreed that it’s important to consider the economic costs and benefits to local communities when addressing these effects, and that addressing these effects can improve quality of life.

Related links:

Access the national combined results report here: National Wildlife Refuge Visitor Survey Results: 2010/2011

Access the Individual refuge results here (all 53 files available): National Wildlife Refuge Visitor Survey 2010/2011: Individual Refuge Results

U.S. Fish and Wildlife Service News Releases

For More Information, Contact: Natalie Sexton

A Gillette's checkerspot butterfly visiting sneezeweed. Credit: A. Miller-Rushing

As the climate has warmed, many plants are starting to grow leaves and bloom flowers earlier. A new study published in the journal, Nature, suggests that most field experiments may underestimate the degree to which the timing of leafing and flowering changes with global warming.

Understanding how plants are responding to climate change will help develop more accurate indicators of spring, forecast the onset of allergy season or the chances of western wildfires, manage wildlife and invasive plants, and help inform habitat restoration plans.

In this new study, scientists evaluated the sensitivity of plants to changes in temperature using two sources: experimental plots versus historical observations from natural sites.

The experiments analyzed in this study were conducted by artificially inducing warming in small study plots, and then measuring plant responses. The historical observations entailed long-term monitoring of multiple species at natural ecological research sites without any manipulation. The date of leafing and flowering was synthesized for dozens of warming experiments and monitoring sites across the Northern Hemisphere.

Scientists conclude that compared to warming experiments, historical monitoring shows temperature sensitivity to be four times greater for leafing and over eight times faster for flowering.

Recording how climatic variations and trends impact seasonal events in plants. Credit: A. Miller-Rushing

On average, the warming experiments predicted that every degree rise in Celsius would advance plants’ flowering and leafing from half a day to 1.6 days, while historical observations indicate a temperature sensitivity of about 5 to 6 days per degree Celsius. The finding was strikingly consistent across species and datasets. Conclusions from this study are based on analysis of more than 1600 plant species on four continents.

The study of how climatic variations and trends impact seasonal events in plants and animals is termed “phenology.” This includes when cherry trees or lilacs blossom, when robins build their nests, when salmon swim upstream to spawn, or when leaves turn colors in the fall.

The study was conducted by an interdisciplinary team led by Elizabeth Wolkovich, with the University of British Columbia, and Ben Cook, with NASA-Goddard. The study was funded by the National Science Foundation, the State of California and the University of California, Santa Barbara. The U.S. Geological Survey (USGS) and the USA-National Phenology Network (USA-NPN) also provided support and assisted with assembling and analyzing historical phenological observations and climate data.

Future Tracks: Experiments and Observations

Observing changes in the seasonality of plants in Concord, Massachussets. Credit: A. Miller-Rushing

The authors of the Nature paper recognize the value of both experiments and monitoring. They call for standardization of measurements and protocols as well as improvements in experimental design, and continuation and expansion of long-term monitoring efforts like the USA-NPN.

The USA-NPN brings together citizen scientists, government agencies, non-profit groups, educators and students of all ages to monitor the impacts of climate change on plants and animals in the United States. The USA-NPN was established by the USGS in collaboration with the National Science Foundation.

“This study underscores the reasons for recent establishment of a USA-NPN to help track, understand, and hopefully forecast different species responses to climate variability and change across the U.S.,” said USGS scientist Julio Betancourt, who is a co-author of this new report.

You Can Help! Track the Pulse of our Planet

We need your help to track the pulse of our planet. Through the USA-NPN’s Nature’s Notebook, citizens across the nation are providing data on plants and animals.

People like you — gardeners, farmers, birders, hikers, anglers, joggers, or all-around nature enthusiasts — are already recording the recurring events they see in the lives of the plants and animals around them. This includes when cherry trees or lilacs blossom, when robins build their nests, when salmon swim upstream to spawn, or when leaves turn colors in the fall.

Become involved and sign up through the USA-NPN website, or contact the USA-NPN Executive Director Jake Weltzin at jweltzin@usgs.gov.

Mining bee on great false leopardbane in Concord, Massachusetts. Credit: A. Miller-Rushing

More Information

Read a University of California, San Diego, press release, as well as a NASA feature, on this new article.

Young boys working in a newly cropped field in Africa.

USGS geographer Michael Marshall has been studying the effects of evaporative processes on land – water emitted into the atmosphere from the soil and from plants – in East Africa and in the Sahel belt that crosses north-central Africa. Using output from a land surface model, Marshall found substantial drying over much of the Sahel and East Africa during the growing seasons.

“The Sahel is getting drier, and the land process that buffers the decline in rainfall is breaking down under increased warming,” said Marshall, a postdoctoral scholar with the USGS Western Geographic Science Center based in Flagstaff, Ariz. Marshall studies evapotranspiration – the combined effects of water entering the atmosphere via evaporation from the soil or from a plant surface, as well as transpiration, in which plants open their stomata (pores) to take in carbon from the atmosphere for food.

Most research into the effect of evaporation on global climate change deals with the oceans, since they form more than 75 percent of the earth’s surface. But evaporative processes on land are also important, because these processes can more easily be influenced by human activity and because, in some places, they can have a local effect on climate. Evapotranspiration triggers convection – the movement of columns of air – and rainfall. In the Sahel, evapotranspiration and localized convection are especially important because of the distance from the ocean or other large water bodies.

Using remote sensing satellite data and surface reanalysis data, downscaled from global general-circulation models, Marshall and his team analyzed evaporation in Africa over a 31-year period. In contrast to many Intergovernmental Panel on Climate Change (IPCC) simulations, which predict increased moisture over the Sahel, they identified substantial drying over much of the Sahel during the growing season, particularly in the last 10 to 12 years. To explain the discrepancy, Marshall suggested that the negative impacts of warming temperatures may be overcoming any possible rainfall recovery across the Sahel. He hypothesized that lands converted from natural vegetation to agriculture might have contributed to the change.

A herder moves cattle through a barren landscape in eastern Africa.

“The climate models for Africa tend to be uncertain in general, due to a lack of station data in Africa and the complexity of climate in the tropics. There is still much to be learned,” Marshall said.

Marshall suggested that the new agricultural crops, which have smaller root systems and are in the ground for a shorter time than the native perennials, may be so stressed by their harsh conditions that they are releasing less water into the atmosphere and thus affecting the climate. Very few African farmers have access to irrigation. Thus, any disruption of the process that creates convection and rainfall would greatly affect them in the long term.

Marshall aims in further research to use higher-resolution data to compare satellite and ground information from Africa with data from the central United States and from India, where the movement of air produced by evapotranspiration can also induce rainfall.  He hopes his work will give land managers tools to better understand these regions.

Marshall’s research supports the Famine Early Warning Systems Network (FEWS NET), which helps target more than $1.5 billion of food-related assistance to more than 40 countries each year. The USGS is actively involved in FEWS NET, which is sponsored by the U.S. Agency for International Development (USAID) Office of Food for Peace. FEWS NET examines the populations of the developing world with the most food insecurity, identifying critical situations in which food aid will be needed. Often the populations most in need are those whose livelihoods are tied to subsistence rain-fed agriculture and pastoralism.

Marshall’s findings, published in a recent issue of Climate Dynamics, are available online.

More Information:

Top Story: Science Helping to Save Lives in Africa

Top Pick: Poor Spring Rain Predicted in Africa

Young boys working in a newly cropped field in Africa.

Spring rains in the eastern Horn of Africa are projected to begin late this year and be substantially lower than normal.

From March–May, the rains are expected to total only 60 to 85 percentage of the average rainfall in this region. This is a significant deterioration compared to earlier forecasts.

Lower rain amounts would have significant impacts on crop production, rangeland regeneration for livestock, and replenishment of water resources.

This would put greater stress on the region, particularly Somalia which is still recovering from a famine declared last year, as well as Kenya and Ethiopia which also experienced a severe food crisis. An increase in food insecurity and in the size of the food insecure population is likely.

The State Department released a statement on this forecast and their intent to provide additional funding to aid refuges and drought-affected communities.

Famine Early Warning Systems Network

 The rainfall projections were completed by the Famine Early Warning Systems Network (FEWS NET), which helps target more than $1.5 billion of assistance to more than 40 countries each year. FEWS NET monitors high risk areas of the developing world with the most food insecurity, identifying critical situations in which food aid will be needed.

FEWS NET is sponsored and led by the U.S. Agency for International Development (USAID) Office of Food for Peace. Implementing partners include the U.S. Geological Survey (USGS), Chemonics International, Inc., National Aeronautics and Space Administration (NASA), National Oceanographic and Atmospheric Administration (NOAA), and the U.S. Department of Agriculture (USDA).

USGS Science

A herder moves cattle through a barren landscape in eastern Africa.

The USGS led the climate analysis for the recent FEWS NET rainfall projection.

“Rainfall projections were estimated by looking very closely at all the prior droughts from March–May since 1979 in the eastern Horn of Africa,” said USGS scientist Chris Funk, who led this research. “We found that sea surface temperatures in the western/central Pacific and the Indian oceans are key drivers of rainfall during that time period. So we compared sea surface temperatures from past years to March 2012, and developed an updated rainfall forecast for this spring season.”

Climate modeling analysis was done in collaboration with others, including Greg Husak and Joel Michaelsen with the Climate Hazards Group at the University of California, Santa Barbara, as well as Bradfield Lyon at The International Research Institute for Climate and Society. Lyon’s research identified the important role of the Pacific Ocean in recent droughts.

The USGS also contributes satellite remote sensing data and analysis of vegetation and rainfall to support FEWS NET activities throughout the world. Remote sensing from space allows scientists to provide rapid, accurate assessments of a broad range of environmental and agricultural conditions. A newly completed vegetation monitoring system allows FEWS NET analysts to track conditions across all of Africa in tremendous detail.

“The concerning picture that emerged from FEWS NET climate monitoring services was that despite the good rains of the past winter, the situation east Africa has deteriorated very rapidly, to a point that the water deficits and vegetation health looked as bad as this time last year,” said Funk.

Link between Sea Surface Temperatures and Rainfall

 As the globe has warmed over the last century, the Indian and central/western Pacific oceans have warmed particularly fast. USGS scientists found that the warming of these oceans affects rainfall over large areas of the Horn of Africa.

The resulting warmer air and increased humidity over the Indian and Pacific oceans produce more frequent rainfall over the oceans. The air then rises over the equatorial Indian and Pacific oceans, and flows westward, descending over Africa. Since the air has already lost moisture from rainfall over the oceans, this leads to decreased rain amounts in parts of eastern Africa. Trends toward increased frequency of drought that we are seeing now appear likely to continue into the future as warming continues.

“Essentially, our research has progressed to the point where we can recognize fairly well the climate patterns linked to the recent droughts, and we hope this helps identify potential bad seasons in advance to raise awareness,” said Funk.

More Information

Learn more about USGS science helping to save lives in Africa.

Listen to a podcast interview on FEWS NET and USGS research in Africa.

This image, from April 2004, shows mortality of some adult Joshua trees resulting from years of hot-dry climate. During the prior year, this area received only 17 percent of its average precipitation and was 4 degrees F warmer than average -- conditions that are projected to become even more frequent in models of future climate. Seedlings and saplings in this southerly stand of Joshua trees are rare to non-existent.

As the climate gets warmer, many forests are feeling the heat. Impacts range from increased forest fire hazards and tree mortality to detrimental beetle outbreaks and alterations to leaf abundance and bloom.

When forest cover or composition changes, there are impacts to the availability of wood products, clean water, recreational opportunities, and habitats for many plants and animals.

In recognition of World Forestry Day, let’s take a glimpse at U.S. Geological Survey science to understand the fate of forests from climate change.

To sustain the health and production of America’s forests, managers need sound science to guide their decisions. The USGS is involved in several initiatives across the nation and in other countries to provide science to understand climate change impacts to forests.

A prescribed fire lights up the night at Sequoia National Park, California. USGS scientists are investigating how fire in an era of climate change are affecting forests across the United States. Credit: USGS, Nate Stephenson

USGS scientists are working to detect what forest changes are happening and the associated impacts, while also developing forecasts and scenarios for what may happen in the future. Scientists are even looking at the potential for our nation’s vegetation, soils and sediments to soak up and store carbon from the atmosphere. This science is the basis on which strategies are developed to manage and protect these environments.

What Changes are Happening Now and in the Future?

Scientists are identifying how climate change is impacting forests by answering questions such as: What’s happening, why, what does it mean, and what does the future hold?

Forest Fires

There is a growing realization that climate warming may be linked to increasing forest fire size, severity, and frequency.  Hotter temperatures result in reduced winter snowpack, earlier snowmelt, longer summer drought, and therefore drier conditions that are more susceptible to fire ignition.

Forest Die-off

USGS scientists have found that warmer temperatures and associated stress from drought are contributing to increased tree mortality in all major forest types around the world. The USGS is developing models to forecast expected changes in tree distributions given projected changes in climate. In the Southwest, for example, Joshua trees will likely be eliminated from 90 percent of their current range in 60 to 90 years. Other USGS research has also identified a rapidly rising death rate for trees in old-growth forests across the West.

Beetle Outbreaks

Hotter temperatures may contribute to outbreaks of insects or diseases, both native and non-native, which are harmful to forests. USGS scientists have linked some recent outbreaks of tree-killing bark beetles in the West to warming temperatures. In Colorado, the USGS is working to evaluate whether and how forest management practices (such as thinning or prescribed burning) increase or decrease forests’ resilience to a currently destructive native insect, the mountain pine beetle.

A hemispherical photo from Pocosin weather station site, Shenandoah National Park.

Leaf Growth and Abundance

As climate changes, it affects the timing of when leaves emerge, the amount of foliage that grows as well as the timeframe when leaves begin to fall. The study of the timing of such events as related to climate is termed “phenology.” USGS scientists are studying how forest phenology may be impacted by climate change, focusing research on Shenandoah National Park in Virginia. Understanding forest phenology patterns is important because it affects water resources, habitat condition, the timing of allergy seasons, vacation planning and tourism, and carbon storage.

Storing Carbon in Forests

Trees naturally soak up CO₂ from the air through photosynthesis. Forests absorb about ¼ of annual anthropogenic (human created) carbon emissions that would otherwise contribute to atmospheric warming.

USGS scientists are assessing the potential of ecosystems to store carbon in vegetation, soils and sediments, which is a process known as biological carbon sequestration. The assessment will help inform land management decisions such as wetland restoration, forest harvesting, or farming techniques. A USGS assessment on the amount of carbon stored in ecosystems across the nation is expected to be completed around 2013.

The USGS is also actively involved in SilvaCarbon, helping countries build the capacity to monitor and manage their forests and carbon. In a collaborative effort, U.S. Federal agencies have been conducting national assessments in Gabon, Indonesia, Colombia, Ecuador and Peru. They are also providing training workshops such as techniques for forest mapping and how to link ground, aerial and satellite observations. SilvaCarbon also contributes to the Group on Earth Observations (GEO) Forest Carbon Tracking initiative.

Forest Science Requires Long-Term Monitoring and Research

Scenic shots of Rocky Mountain National Park, Mountain Pine Beetle damage to pine forest.

Part of the challenge for understanding how forests are affected by climate change is the need for long-term data. Satellites are a cost-effective way to gather wide-spread information on forests, and the USGS Landsat program has been doing so across the globe since 1972. Landsat records provide the world’s longest continuous collection of space-based data.

The world’s longest ongoing annual record of forest data is in Sequoia and Yosemite national parks in California. For 30 years, the USGS has been tracking the birth, growth, health and deaths of some 30,000 individual trees in these parks. Research is coordinated through the USGS Western Mountain Initiative climate change project.

Start with Science

Long-term monitoring and sound science on climate change impacts to our forests is needed to make the most informed decisions to protect these environments.

Contact: Jessica Robertson