FAQ's about Climate

A drought is a period of drier-than-normal conditions that results in water-related problems. Precipitation (either rain or snow) falls in uneven patterns across the country. The amount of precipitation at a particular location varies from year to year, but over a period of years, the average amount is fairly constant. In the deserts of the Southwest, the average precipitation is less than 3 inches per year. In contrast, the average yearly precipitation in the Northwest is more than 150 inches.

When no rain or only a very small amount of rain falls, soils can dry out and plants can die. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers declines, water levels in lakes and reservoirs fall; also the depth to water in wells increases. If dry weather persists and water-supply problems develop, the dry period can become a drought.

Reference: Moreland, 1993, Drought: U.S. Geological Survey Water Fact Sheet, Open-File Report 93-642

The current El Niño will probably surpass the greatest El Niño of century, that of 1982-83. During the past 40 years, nine El Niños have affected the western coasts of North and South America. Most of them raised water temperatures along 5000 miles of coast. The weaker events raised sea temperatures only a few degrees Fahrenheit and caused mild changes in weather. But the strong ones, like the El Niño of 1982-83, left a climatic imprint that was global in extent.

El Niño recurs irregularly, from two years to a decade, and no two events are exactly alike. Before the 1982-83 El Niño event, scientists did not collect detailed information on El Niños, so information is scanty for making high-quality predictions about the effects of the current El Niño of 1997-98.

The impacts of El Niños can be devastating, as illustrated by some of the effects of the unusually strong El Niño of 1982-83:

- Drought (sometimes with associated wildfires) in many nations (particularly in the western Pacific Rim, southern and northern Africa, southern Asia, southern Europe, and parts of South and Central America);- Severe cyclones that damaged island communities in the Pacific;- Flooding over wide areas of South America, western Europe, and the Gulf Coastal states; - Severe storms in the western and northeastern United States.

Go to the Energy Resources website at http://energy.usgs.govfor a newly released gas hydrates assessment of the North Slope of Alaska. A fact sheet is at http://pubs.usgs.gov/fs/2008/3073.

No one knows for sure what would happen if the snow and ice in the polar regions all melted. Sea level would rise, which would flood coastal regions. Climate would be affected worldwide. Isostatic rebound would occur where ice masses were removed from continents, causing the land surface there to rise. Many scientists are trying to predict the effects of climate changes such as a general warming trend by using computer climate models. Much more research needs to be done before we can confidently predict results.

Not specifically. Our charge is to understand characteristics of the earth, especially the earth's surface, that affect our Nation's land, water, and biological resources. That includes quite a bit of environmental monitoring. Other agencies, especially NOAA and NASA, are specifically funded to monitor global temperature and atmospheric phenomena such as ozone concentrations. Our work at USGS in the Global Change and Climate History Program focuses on understanding the likely consequences of climate change, especially by studying how climate has changed in the past.

The USGS estimates that there are 85.4 trillion cubic feet of undiscovered, technically recoverable gas from natural gas hydrates on the Alaskan North Slope. This is the first-ever resource estimate of technically recoverable natural gas hydrates in the world.

This assessment shows that gas hydrates could add significantly to the U.S. energy mix. The Alaskan North Slope holds one of the nation's largest deposits of technically recoverable natural gas.

Devils Hole is a tectonic cave developed in the discharge zone of a regional aquifer in south-central Nevada. The walls of this predominantly subaqueous cavern are coated with dense vein calcite. The stable isotopic content of the calcite provides a 500,000-year record of variations in temperature and other paleoclimatic parameters.

See:

Winograd, I.J., Coplen T.B., Landwehr, J.M., Riggs, A.C., Ludwig,K.R., Szabo, B.J., Kolesar, P.T., and Revesz, K.M., 1992, Continuous 500,000-year climate record from vein calcite in Devils Hole, Nevada: Science, v. 258, p. 255-260.

Riggs, A.C., Carr, W.J., Kolesar, P.T., and Hoffman, R.H., 1994, Tectonic speleogenesis of Devils Hole, Nevada, and implications for hydrogeology and the development of long, continuous paleoenvironmental records: Quaternary Research, v. 42, p. 241-254.

If another catastrophic caldera-forming Yellowstone eruption were to occur, it quite likely would alter global weather patterns and have enormous effects on human activity, especially agricultural production, for many years. In fact, the relatively small 1991 eruption of Mt. Pinatubo in the Philippines was shown to have temporarily, yet measurably, changed global temperatures. Scientists, however, at this time do not have the predictive ability to determine specific consequences or durations of possible global impacts from such large eruptions.

An effort was undertaken to identify and assemble USGS records of daily mean discharge that were judged to be relatively free of anthropogenic effects. The resulting collection of stations is called the Hydroclimatic Data Network or HCDN. The HCDN consists of 1,659 sites throughout the United States and its territories, totaling 73,231 water years of daily mean discharge values.

For more information about this network, visit http://pubs.usgs.gov/of/1992/ofr92-129.

Six criteria by which station records were examined for suitability for inclusion in the Hydro-Climatic Data Network , or HCDN were defined as follows:

1. Breadth of coverage -- To insure the broadest possible temporal and geographic coverage with representation of diverse climatic and watershed conditions, records from any station held by the USGS, whether currently active or not, were examined for any water year through water year 1988. (A water year is defined to be the 12-month period, beginning on October 1 continuing through September 30 and is labeled according to the ending calendar year, that is, in which September 30 occurs.) Note that as a gage's watershed conditions change, criteria satisfaction can also change, so that suitability of any record for any gage after water year 1988 cannot be assumed.
   
   
2. Length of record -- A record of at least 20 water years of suitable monthly discharge data was preferred. However, if an otherwise acceptable record was shorter than 20 water years but that record was available for a uniquely located surface-water gaging station, one that was located in an otherwise underrepresented geographic area or climatic condition, then that record was included in the HCDN. Conversely, if a long record was available for a station but only a portion of the record was suitable by the HCDN criteria, then only the unimpaired part of the record was selected for inclusion in the final data set. Explanatory comments are provided if the selected record was shorter than 20 years or if it was less than the entire period of record available for the station.
   
   
3. Unimpaired basin conditions, at least with respect to the computation of a monthly mean discharge value -- There should be no overt adjustment of "natural" streamflow, such as flow diversion or augmentation, regulation of the streamflow by some containment structure, or reduction of base flow by extreme ground-water pumping, nor should the degree of human activity in the watershed, such as changes in land use during the period of record, be so large as to significantly affect the value of monthly mean discharge (computed on the basis of the daily mean discharge) at the station. Even if the entire station record was not currently suitable because of regulation, diversion, augmentation and so forth, but some portion of the period of record was acceptable by the specified criteria, then the suitable period and only the suitable period was included in the HCDN. A streamflow record was considered suitable for inclusion in the HCDN if the monthly mean discharge values met the criterion for nonimpairment of "natural" streamflow conditions. However, for the majority of records, even the daily mean discharges satisfy this criterion.
   
   
4. Accuracy of the records -- The predominant accuracy rating assigned by the USGS had to be at least "good" for the record of daily mean discharges in those water years chosen. An accuracy of "good" implies that 95 per cent of the daily mean discharge values are assessed to be at least within 10 per cent of the true value. (A discussion of the accuracy of the records and the assignment of ratings can be found in the USGS Water-Data Reports for each State, published annually, as well as in the 982 report by S.E. Rantz and others, Measurement and Computation of Streamflow, U.S. Geological Survey Water-Supply Paper 2175. )
   
   
5. Measured discharge values -- The discharge data reported in the records have been obtained by means of standard measurement practices followed by the USGS. Occasionally, some discharge values in the published record will be designated as "estimated". Such a designation arises when the stage height recorder malfunctions, for example, due to ice conditions. If there is an excessive number of estimated values in the monthly record, the assigned rating will be less than "good" and the record will be disqualified by the accuracy criterion. Also, if there is a measured diversion upstream from a surface-water gaging station, such as for irrigation, which is routinely and simply added onto the streamflow measured at the gaging site, then the corrected discharge record was used in the HCDN, but with a comment qualifying the station's record. However, the HCDN contains no records that are "constructed", that is, do not correspond to the flow in any single natural channel, nor does the HCDN contain records that are re-constructed using information from other sites or information on activities such as diversions, augmentation, pumping, and regulation. Neither was any attempt made to extend or "fill in" sections of records with missing values using some computational algorithm. Thus, one need not ask if any patterns found in the time series have been introduced by the choice of computational algorithm to extend the records.
   
   
6. Availability of data in electronic form -- Because of the functional requirement to handle large quantities of information, data had to be available in electronic format in the USGS national streamflow database.

See: J.R. Slack and Jurate Maciunas Landwehr, 1992, HCDN: A U.S. Geological Survey streamflow data set for the United States for the study of climate variations, 1874 – 1988, USGS Open-File Report 92-129

No one knows for sure. In the Devils Hole, Nevada paleoclimate record, the last four interglaciations lasted over ~20,000 years with the warmest portion being a relatively stable period of 10,000 to 15,000 -years duration. This is consistent with what is seen in the Vostok ice core from Antarctica and several records of sea level high stand, and would suggest that an equally long duration should be inferred for the current interglacial period as well. Work in progress on Devils Hole data for the period 60,000 to 5,000 years ago indicates that current interglacial temperature conditions may have already persisted for 17,000 years. Other workers have suggested that the current interglaciation might last tens of thousands of years.

See:

Winograd, I.J., Landwehr, J.M., Ludwig, K.R., Coplen, T.B., and Riggs, A.C, 1997, Duration and structure of the past four interglaciations: Quaternary Research, v. 48, p. 141-154.

Muhs, D.R., Simmons, K.R., and Steinke, B., 2002, Timing and warmth of the last interglacial period: New U-series evidence from Hawaii and Bermuda and a new fossil compilation for North America: Quaternary Science Reviews, v. 21, p. 1355-1383.

Paillard, D., 2001, Glacial cycles: Toward a new paradigm: Reviews of Geophysics, v. 39, p. 325-346.

Explore the variety of USGS resources on polar research, from maps and fact sheets to photographs and databases. Especially note Fact Sheet 2007-3013, "International Polar Year: Science at the Ends of the Earth".

There are many different reasons for why animals become endangered, especially habitat loss. An animal's habitat is where they live, eat, and raise their young. Protecting endangered and threatened species and restoring them to a secure status in the wild is the primary objective of the endangered species program of the U.S. Fish and Wildlife Service, an agency of the Department of the Interior. Their Endangered Species Web site can be accessed at http://endangered.fws.gov.