Consequences of global warming in California

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The consequences of global warming in California are among the regional and local effects of global warming .

temperature

Worldwide, the air temperature near the ground rose by an average of 0.85 ° C between 1880 and 2012 . One of the regions particularly affected is the west of North America, with a temperature increase around 70% higher than the global average. This is primarily due to the fact that the arid land areas in the western United States are warming significantly faster than the ocean . In the period between 1950 and 2000 alone, there was an average increase in air temperature of 0.99 ° C in California. The minimum temperatures rose more than the maximum temperatures. Regionally, the largest temperature increases were observed in southern California, where urbanizationis strongest. In regions with strong agricultural irrigation , the temperature rise was less than in arid areas.

Snowfall

The direct consequences of this temperature development that can already be observed include lower snowfall and lower probabilities of the formation of a snow cover in the mountains, v. a. at low and medium altitudes, and an earlier start of snowmelt. According to climate models, there will be no more snowfall below 1000 meters in California after 2070. This development has a significant impact on the water supply in some areas .

drought

An increase in the duration and intensity of the California drought is observed and a continuation of this development is predicted. According to these projections, the risk of drought in the 21st century will exceed the drought periods of the 20th century and even the driest decades during the Medieval Warm Period . The most pronounced drought of the past 1200 years began in 2011 and lasted until 2015 (see drought in California since 2011 ).

An unusual high pressure ridge over the American West, which prevents low pressure areas (with precipitation) from reaching the mainland, has been discussed as a possible mechanism behind the emergence of the drought in California since 2011 . Analyzes of this high pressure ridge in the winter of 2013/2014 showed that it arose in late summer due to the influence of continuous Rossby wave energy in the western North Pacific , which intensified in winter. The high pressure ridge caused wave energy to rise in the direction of the wind, further strengthening the low pressure trough over the northeastern United States, creating a dipole . Instead of reacting to the El Niño-Southern Oscillation (ENSO) and the Pacific Decade Oscillation (PDO) as usual (ENSO was in a nearly neutral state and the PDO was not very pronounced), the dipole and the associated circulation pattern correlated with an ENSO precursor (the "Western North Pacific Pattern"). This connection has become increasingly pronounced since the 1970s, which, according to climate models, is associated with the increased proportion of greenhouse gases in the atmosphere. This indicates that the investigated high pressure ridge in winter 2013/2014 and the associated drought are a possible consequence of anthropogenic global warming . The working group around Noah Diffenbaugh from Stanford University also came to a similar conclusion.

Web links

literature

Individual evidence

  1. ↑ IPCC : Fifth Assessment Report of the IPCC Partial Report 1 (Scientific Basis) ( Memento of the original of 23 September 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (German summary of the BMU , BMBF , IPCC and UBA ). October 2013. Retrieved April 12, 2015. @1@ 2Template: Webachiv / IABot / www.de-ipcc.de
  2. ↑ Susan Moser, Guido Franco, Sarah Pittiglio, Wendy Chou, Dan Cayan: The Future Is Now: An Update on Climate Change Science Impacts and Response Options for California . California Energy Commission , PIER Energy ‐ Related Environmental ResearchProgram, 2009.
  3. ↑ Steve LaDochy, Richard Medina, William Patzert: Recent California climate variability: spatial and temporal patterns in temperature trends . In: Climate Research . 33, 2007, pp. 159-169. doi : 10.3354 / cr033159 .
  4. ^ Daniel R. Cayan, Edwin P. Maurer, Michael D. Dettinger, Mary Tyree, Katharine Hayhoe : Climate change scenarios for the California region . In: Climatic Change . 87 (Suppl. 1), 2008, pp. S21-S42. doi : 10.1007 / s10584-007-9377-6 .
  5. ^ Norman L. Miller, Kathy E. Bashford, Eric Strem: Potential impacts of climate change on California hydrology . In: Journal of the American Water Resources Association . 39, No. 4, August 2003, pp. 771-784.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: dead link / esd.lbl.gov  
  6. ^ Edward R. Cook, Connie A. Woodhouse, C. Mark Eakin, David M. Meko, David W. Stahle: Long-Term Aridity Changes in the Western United States . In: Science . 306, November 2004, pp. 1015-1018. doi : 10.1126 / science.1102586 .
  7. ^ Benjamin I. Cook, Toby R. Ault, Jason E. Smerdon: Unprecedented 21st century drought risk in the American Southwest and Central Plains . In: Science Advances . 1, No. 1, February 2015, p. E1400082. doi : 10.1126 / sciadv.1400082 .
  8. ↑ S.-Y. Simon Wang, Lawrence Hipps, Robert R. Gillies, Jin-Ho Yoon: Probable causes of the abnormal ridge accompanying the 2013-14 California drought: ENSO precursor and anthropogenic warming footprint . In: Geophysical Research Letters . 41, No. 9, May 2014, pp. 3220-3226. doi : 10.1002 / 2014GL059748 .
  9. ↑ Daniel L. Swain, Michael Tsiang, Matz Haugen, Deepti Singh, Allison Charland, Bala Rajaratnam, Noah S. Diffenbaugh: The Extraordinary California Drought of 2013/14: Character, Context, and the Role of Climate Change . (PDF) In: Bulletin of the American Meteorological Society (Special Supplement: Explaining Extreme Events of 2013 from a Climate Perspective) . 95, No. 9, September 2014, pp. S3-S7.
  10. ↑ Christopher Schrader : Climate change favored drought in California. On: Süddeutsche.de , September 30, 2014. Accessed December 1, 2014.