Our Changing Climate

The report warns that California faces significant risks from global warming, with projected temperature increases between 3°F and 10.5°F by the end of the century. These changes threaten to severely reduce Sierra Nevada snowpack, increase the frequency of large wildfires, degrade air quality, and disrupt the state's $30 billion agriculture industry. The document emphasizes that while some changes are unavoidable, the most severe consequences can be avoided by reducing heat-trapping emissions to levels that keep warming within the lower range of 3 to 5.5°F.

• California's average temperatures are projected to rise between 3°F and 10.5°F by the end of the century, depending on the emissions scenario. A lower emissions rate would limit warming to 3 to 5.6°F, while medium to high rates could lead to increases of 4.7 to 10.5°F.
• Global warming is expected to severely impact water resources by reducing the Sierra Nevada spring snowpack by 70% to 90% if emissions continue unabated. This loss would challenge water managers, hinder hydropower generation, and potentially reduce the water supply for farmers by up to 25%.
• Public health risks will increase due to worsening air quality and more extreme heat. In the medium warming range, Los Angeles and the San Joaquin Valley could see a 75% to 85% increase in days conducive to ozone formation. By 2100, the higher warming range could add up to 100 more days per year above 90°F in Los Angeles and 95°F in Sacramento.
• The state's $30 billion agriculture industry faces threats to crop quality and quantity. High temperatures may cause wine grapes to ripen one to two months earlier by the end of the century, and milk production could decrease by up to 20% under the higher warming range.
• Natural landscapes are at risk from increased wildfires and shifting vegetation. The risk of large wildfires could increase by as much as 55% in the medium warming range. Additionally, alpine and subalpine ecosystems could decline by 60% to 80% by the end of the century.
• Rising sea levels threaten the California coastline, with a projected increase of 22 to 35 inches by the end of the century under the higher warming range. This would accelerate coastal erosion, inundate areas with saltwater, and increase the frequency of storm-surge-induced flood events.

APA

Luers, A. L., Cayan, D. R., Franco, G., Hanemann, M., & Croes, B. (2006). Our Changing Climate. Union of Concerned Scientists. https://www.ucs.org/sites/default/files/2019-09/our-changing-climate-final.pdf

Chicago

Luers, Amy Lynd, Daniel R. Cayan, Guido Franco, Michael Hanemann, and Bart Croes. Our Changing Climate. Union of Concerned Scientists, 2006. https://www.ucs.org/sites/default/files/2019-09/our-changing-climate-final.pdf.

Wikipedia

{{cite report |last1=Luers |first1=Amy Lynd |last2=Cayan |first2=Daniel R. |last3=Franco |first3=Guido |last4=Hanemann |first4=Michael |last5=Croes |first5=Bart |title=Our Changing Climate |publisher=Union of Concerned Scientists |date=July 2006 |url=https://www.ucs.org/sites/default/files/2019-09/our-changing-climate-final.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{luers2006our, author = {Luers, Amy Lynd and Cayan, Daniel R. and Franco, Guido and Hanemann, Michael and Croes, Bart}, title = {{Our Changing Climate}}, institution = {Union of Concerned Scientists}, year = {2006}, month = jul, url = {https://www.ucs.org/sites/default/files/2019-09/our-changing-climate-final.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }