The warmer the air near the surface is relative to the air above it, the more potential energy it has to move up. This circulation brings thunderstorms and rainfall to the monsoon region, providing much of their annual total precipitation. Right:Graph of the lake's changing level over time. Home Regions Southwest Key Points: Columbian mammoth (Mammuthus columbi) tracks, Pleistocene, White Sands National Park, New Mexico. Download related technical information PDF, https://droughtmonitor.unl.edu/DmData/DataTables.aspx, A Closer Look: Temperature and Drought in the Southwest. Maps modified from maps by Wade Greenberg-Brand, originally published inThe Teacher-Friendly Guide to the Earth Science of the SouthwesternUS, after figure 3 in L. Grande (2013) The Lost World of Fossil Lake. The white arrow is pointing to one of the leaflets of a compound leaf. JavaScript appears to be disabled on this computer. Of the southwestern states, Arizona emits the most greenhouse gases, releasing 92.5 million metric tons of energy-related carbon dioxide (CO2) in 2019. Its remnant exists today as the Great Salt Lake. Data source: NOAA, 20212Web update: April2021. This page uses Google Analytics. Acad. Summer heat waves will become hotter and longer, while winter cold snaps will occur less often. Earth 300 million years ago, during the end of the Carboniferous Period (Pennsylvanian). ; Precipitation was above-average across portions of the Great Basin and Southwest, from the southern Plains to the Great Lakes and across much of the eastern U.S. Mississippi had its wettest summer on record with Alabama, Michigan, New York and Massachusetts . During winter months, daytime temperatures may average 70 degrees F, with night temperatures often falling to freezing of slightly below in the lower desert valleys." Photo by James St. John (flickr, Creative Commons Attribution 2.0 Generic license, image cropped and resized). The Cretaceous-Paleogene boundary at Trinidad Lake State Park, Las Animas County, Colorado. NWS Climate Prediction Center College Park MD. Kppen climate map of the 48 contiguous states of the continental United States. In the late Eocene, the Earth began to cool, and global temperatures fell sharply at the boundary between the Eocene and Oligocene epochs (approximately 35 million years ago), due in part to the separation of South Americas southern tip from Antarctica. The Wave, a series of intersecting U-shaped troughs eroded into Jurassic NavajoSandstone within the Paria Canyon-Vermilion Cliffs Wilderness, Arizona. Fossil mammals adapted to colder temperatures are found in the Pleistocene of Colorado. Photo of USNM P 38052 by Frederic Cochard (Smithsonian National Museum of Natural History, public domain). This led to global cooling and dropping global sea levels. Accessed March2021. www.ncdc.noaa.gov/cag. Fig. Branches and leaves of an ancient conifer (Walchia dawsonii), Permian Hermit Shale, Arizona. Climate change is affecting the Southwest's water resources, terrestrial ecosystems, coastal and marine environments, agriculture, and energy supply. Creative Commons Attribution 2.0 Generic license, Scenarios for Climate Assessment and Adaptation, Image by The High Fin Sperm Whale, created from images by NOAA National Weather Service training material (Wikimedia Commons, public domain), Creative Commons Attribution-ShareAlike 4.0 International license, Modified from a map by Adam Peterson (Wikimedia Commons, Photo by Bob Wick, Bureau of Land Management (flickr, public domain), Creative Commons Attribution-ShareAlike 3.0 Unported license, Photo by Richard Stephen Haynes (Wikimedia Commons, Photo of USNM PAL 165239 by Crinoid Type Project (Smithsonian National Museum of Natural History, public domain), Photos of YPM IP 529539 by Jessica Utrup, 2015 (Yale Peabody Museum of Natural History/YPM, CC0 1.0 Universal/Public Domain Dedication, Photo of USNM P 38052 by Frederic Cochard (Smithsonian National Museum of Natural History, public domain), Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Generic license, Cretaceous Atlas of Ancient Life: Western Interior Seaway, Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International, Photo of USNM 166396 from the Cretaceous Atlas of Ancient Life, Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International license, Inset image from the NASA Jet Propulsion Laboratory (PIA03397), Photo by Jeffrey Beall (Wikimedia Commons, Creative Commons Attribution 4.0 International license, Photo by Kenneth Carpenter (Wikimedia Commons, Creative Commons Attribution-NonCommerical 2.0 Generic license, Photo by Center for Land Use Interpretation, Creative Commons Attribution-Noncommercial-ShareAlike 3.0 license, Creative Commons Attribution-ShareAlike 2.0 Generic license, Photo by Dr. David Goodrich, NOAA (NOAA Photo Library ID wea04192, NOAA's National Weather Service, via flickr, Images by Lauren Dauphin, NASA Earth Observatory, Photos by Lauren Dauphin, NASA Earth Observatory, NASA Earth Observatory image by Lauren Dauphin (NASA Earth Observatory, Photo by Santa Fe National Forest (National Interagency Fire Center on flickr, public domain), https://earthathome.org/de/talk-about-climate/, https://earthathome.org/de/what-is-climate/, https://earthathome.org/de/recent-climate-change/, https://earthathome.org/de/climate-change-mitigation/, https://earthathome.org/de/climate-change-adaptation/, https://earthathome.org/quick-faqs/#climate, Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International licenses. Not really sure if it's possible to even find that rabbit hole let alone getting to the end of it :) Good luck. The southwestern desert is hot, with winter daytime temperatures in the lower 60s and average summer daytime temperatures between 105 and 115F. Here at the ENSO Blog, were always curious about the role of ENSO (El Nio/Southern Oscillation, the entire El Nio/La Nia system). Taken on August 15, 2016. Bark beetles, which normally die in cold weather, have been able to survive through the winter and reproduce, increasing tree mortality. Figure by Ingrid Zabel for PRI's [emailprotected] project (CC BY-NC-SA 4.0 license). You mentioned, if I understood correctly, that a La Nina pattern during winter months leads to an increase in the North American Monsoon in late summer. The Southwest is also definable, to an extent, by environmental conditions - primarily aridity. Volcanic activity was strong. Used under a Creative Commons license. Percent of total annual precipitation occurring during JulySeptember, based on 19792020 using CPC Unified rain-gauge-based data. Studies show that the southwestern states' climate is changing right now and that change has accelerated in the latter part of the 20th century. The final ingredient is wind. A strong difference in air temperature at different heights creates instability; the warmer the air near the surface is relative to the air above it, the more potential (stored) energy the warm air has to move up, and the more potential for a storm. Photo by James St. John (flickr, Creative Commons Attribution 2.0 Generic license, image resized). Declining water supplies, reduced agricultural yields, health impacts in cities due to heat, and flooding and erosion in coastal areas are additional concerns. The large ice sheets in the Northern Hemisphere did not extend into the Southwest, even at their maximum area. Agua Caliente solar farm, Maricopa County, Arizona. Photo by James St. John (flickr,Creative Commons Attribution 2.0 Generic license, image cropped and resized). Natural variability, changes in irrigation practices, and other diversions of water for human use can influence certain drought-related measurements. The Great Plains receive warm, moist air moving north from the Gulf of Mexico, and cold, dry air moving in from the Rocky Mountains and the northern U.S. Where these air masses meet, vigorous mixing causes thunderstorms. A couple of field campaigns, including the Arizona-based South-West Monsoon Project (SWAMP, 1993) and the international North American Monsoon Experiment (NAME, 2004), provided a lot of observational data and resulted in a better understanding of the mechanics of the monsoon. This chapter builds on assessments of climate change in the Southwest region from the three previous U.S. National Climate Assessments. Droughts also contribute to increased pest outbreaks and wildfires, both of which damage local economies, and they reduce the amount of water available for generating electricityfor example, at the Hoover Dam.1. After the end-Cretaceous bolide impact, the climate may have cooled briefly, but it soon rebounded to a warmer state. The monsoon starts to develop in Mexico in June, and moves into the U.S. Southwest in July. The American Southwest might evoke images of a hot, dry landscapea land of rock, canyons, and deserts baked by the sun. This salt is part of the Late Carboniferous (Pennsylvanian) Paradox Formation. In general, places in the east and south of the UK tend to be drier, warmer, sunnier and less windy than those further west and north. Thick salt deposits accumulated in the northwestern Four Corners area as the seas evaporated. Light precipitation travels eastward over the Sierra Nevada and Cascade mountains after dropping heavy snowfall in areas of high elevation. Higher atmospheric moisture content has also been correlated with an increased incidence of tornados and winter storms. contiguous U.S. (CONUS) into the Northern Plains. Image by The High Fin Sperm Whale, created from images by NOAA National Weather Service training material (Wikimedia Commons, public domain). however, the monsoons provide life-giving moisture in a region that is always dry. Weather conditions, particularly hot, dry weather and wind that spreads flames, contribute significantly to the ignition and growth of wildfires. The Palmer Index is calculated from precipitation and temperature measurements at weather stations, and has been used widely for many years. Its largely too soon to tell. The globe about 485 million years ago, near the Cambrian-Ordovician boundary. Figures 2 and 3 show two ways of measuring drought in the Southwest: the Drought Monitor and the Palmer Drought Severity Index. So is climate change increasing monsoon variability? For many of us, the word monsoon conjures images of heavy rain lasting for months. Record high temperatures for the Southwest range from 53C (128F) in Arizona to 47C (117F) in Utah, while record low temperatures range from 56C (69F) in Utah to 40C (40F) in Arizona. Accessed March 2021. www.ncdc.noaa.gov/cag. Scale bar = 1 centimeter (about 0.4 inches). A major contributing factor to this event was a geological change that occurred far to the south. Changes in atmospheric pressure during the late fall and winter can lead to an accumulation of haze. Notice that North America has separated from Africa and there is a spreading center in the Central Atlantic Ocean. July 1August 22, 2021 precipitation shown as a percent of the average July 1August 22, based on 19792020. Although there has so far been little regional change in the Southwests annual precipitation, the areas average precipitation is expected to decrease in the south and remain stable or increase in the north. Earth 150 million years ago, near the end of the Jurassic Period. Left photoandright photoby NPS/Michael Quinn (Grand Canyon National Park via flickr,Creative Commons Attribution 2.0 Generic license, images cropped and resized). Photo by Richard Stephen Haynes (Wikimedia Commons, Creative Commons Attribution-ShareAlike 4.0 International license, image resized). Water vapor animation for the afternoon of August 22, 2018 showing the monsoon circulation and thunderstorm formation (dark blue, green, dark red).