Presentation on theme: "The Basic Science of Climate Change Janina Moretti September 6, 2012."— Presentation transcript:
The Basic Science of Climate Change Janina Moretti September 6, 2012
Overview Basic science of climate change: – What is climate change? What is causing it? Global and local impacts of climate change Climate change tipping points Climate change solutions
Number of scientific studies dealing with “climate change” published in scientific journals between 1993 and 2003: 928 0 Number disagreeing with the global consensus that greenhouse gas pollution has caused most of the warming of the last 50 years: Science, December 3, 2004 Vol. 306, Issue 5702,1686 There is a scientific consensus: greenhouse gas emissions are causing climate change
The greenhouse effect http://www.ecy.wa.gov/climatechange/whatis.htm
In the past 100 years we have been burning a lot of fossil fuels... CO 2 +0.8°C (1.4°F)
CO 2 +0.8°C (1.4°F) Burning fossil fuels increases the concentration of carbon dioxide in the atmosphere
More carbon dioxide in the atmosphere warms the planet CO 2 +0.8°C (1.4°F)
We are already experiencing climate change impacts Temperature rise Sea level rise Loss of glaciers More frequent extreme weather events (droughts, floods, hurricanes, wildfires) Ocean acidification
Temperature is rising http://www.nasa.gov/home/hqnews/2012/jan/HQ_12-020_2011_Global_Temp.html 9 of the 10 warmest years in the modern meteorological record have occurred since the year 2000 July was the hottest on record for the United States (27,000 high temperature records were broken or tied.)
The Arctic is currently warming at twice the rate of the rest of the world 19792007 Between 1979 and 2007, the Arctic lost over 40% of its ice
The Arctic is currently warming at twice the rate of the rest of the world
More frequent droughts This summer over half the United States is in extreme or moderate drought. Decreased crop yields have caused a 10% spike in food prices.
Climate change impacts San Diego County More intense and frequent wildfires Water Shortages Beach erosion and coastal flooding http://www.sdfoundation.org/
We need to act fast to avoid triggering feedback loops
More examples: Desertification of the Amazon rainforest Melting of the Greenland ice sheet Melting of the West Antarctic ice sheet Methane release from permafrost melt Monsoon shift in India
How do to avoid tipping points? The Three Simple Numbers 1) 2°C (3.6°F) 2) 565 GT CO 2 565 GT CO 2 3) 2,795 GT CO 2 2,795 GT CO 2
Can we stabilize at 2°C? Business as Usual:95% reduction by 2020: http://climateinteractive.org/simulations/climate-momentum-simulation/climate-momentum
Global major contributors to climate change World Resources Institute, http://earthtrends.wri.org/images/GHG_emissions_by_sector2.jpg
Local major contributors to climate change http://www.fypower.org/pdf/SanDiegoCounty_GHGinventory.pdf In San Diego County, on-road transportation and electricity are the largest contributors to greenhouse gas emissions.
There are many well-understood solutions Solutions Replace fossil fuels with clean renewable sources as well as individual actions as consumers Solutions require both collective action as citizens… Increase gas mileage for cars Conserve electricity, water & gas Increase energy efficiency of existing and new buildings Change land use & transportation to reduce miles traveled Consume less and waste less Stop deforestation Move diets lower on the food chain Carbon tax & dividend Inventory, identify potential solutions, create & implement plan
Climate Facts There is a scientific consensus that the earth is warming due to human caused greenhouse gas emissions. The current atmospheric concentration of carbon dioxide is 392ppm. Before the industrial revolution is was 275ppm. 350ppm is a safe upper limit. The impacts of climate change are happening now and faster than previously though. Nine of the 10 warmest years in the modern meteorological record have occurred since the year 2000. 2°C of global warming is a safe upper limit. We can only emit 565 gigatons CO 2 to stay below this limit. Fossil fuel industries have 2,795 gigatons CO 2 in reserve. In San Diego county, the largest contributors to greenhouse gas emissions are transportation (46%) and electricity (25%). In San Diego county, the impacts of climate change are rising temperatures, water shortage, sea level rise, and more frequent and intense wild fires. There are known solutions to climate change, but we need to implement them quickly, on a large scale.
Useful References Climate Progress: http://thinkprogress.org/climate/issue/http://thinkprogress.org/climate/issue/ The latest news on climate change science, solutions, and politics Skeptical Science: http://www.skepticalscience.com/http://www.skepticalscience.com/ Climate science summarized for a general audience. Includes an extensive list of climate myths debunked. Just the Facts-CA: http://www.opr.ca.gov/s_climatechangefacts.phphttp://www.opr.ca.gov/s_climatechangefacts.php Basic facts and science of climate change