You are hereClimate Change Data is In! Geos Institute releases study for Southern Sierra

Climate Change Data is In! Geos Institute releases study for Southern Sierra

The GEOS Institute issued a DWR funded report “Future Climate, Hydrology, Vegetation, and Wildfire Projections for the Southern Sierra Nevada, California” in May 2014. This was the first information I have seen integrating global and local models into basic climate change data for our watersheds in the San Joaquin Valley. The data provided is significant to all Californians and should be reviewed and understood by water managers throughout the State. Planning today can help us to identify our vulnerabilities and strategies for adaptation to the changes that are already occurring. The term “Irreversible Climate Change” identifies that there are positive feedbacks in our climate system that kick in to such an extent that emission reductions are no longer effective.

The early data released in this report is shocking! Using widely accepted climate models, and integrating these projections with local hydrology data, we begin to see a range of possible or likely changes in our hydrologic system. The report emphasized how dominant evapotranspiration rates were to the potential for hydrologic change (changes in precipitation do not translate directly to changes in water supply). The following represent some standout data released under the ‘business as usual’ climate projections for Southern Sierra:

  • Changes to Sierra Nevada hydrology are already occurring (15.8% declines in snow water equivalents, increased wildfires, 16% increase in frequency and intensity of very heavy precipitation, spring runoff occurring 1 to 3 weeks earlier)
  • Increase in average annual temperature of up to 4.1 degrees Celsius by 2099 (up to 11 degrees Fahrenheit in Summer months)
  • An average of 75% reduced runoff in Summer months (May through September, and reaching up to 95%-97% reduction in late summer)
  • Broad agreement in models of 82% - 86% reduction in annual average snowpack

The report emphasized that the resource models we use today can no longer rely on historic data anticipate future conditions. We need to analyze our regional vulnerabilities to climate change, develop mitigation strategies to reduce greenhouse gasses, and plan for adaptations that will reduce our vulnerabilities to these impacts. I challenge you to question your resource managers and ask them what they are doing to plan for a future with climate change. The data is in!


If you care about our rivers and your water supply, get involved. It’s the responsible thing to do. What can you do?


Go to our website at for an expanded discussion on this report and links,


Attend the event: “Tom Cotter on Extreme Weather and Climate Change” at the June General Meeting of the Tehipite Chapter of the Sierra Club

Date/Time:  Wednesday, June 18, 2014 - 7:00pm

Location: UC Center, 550 E. Shaw Ave., Fresno across from Fashion Fair.


Go to the website and attend their regular planning meetings and check out the GEOS Institute website for detailed reports


Join Citizen’s Climate Lobby. More info at CCL website

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