Climate change science: Why should California care?

Transcription

1 Climate change science: Why should California care? Chris Field Carnegie Institution: Department of Global Ecology Stanford University: Department of Environmental Earth System Science Department of Biology

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3 Toles, time machine

4 Article 2 of the UNFCCC The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

5 Article 2 of the UNFCCC The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

6 Article 2 of the UNFCCC The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

7 Risk = probability x consequence Loaded dice Car driving toward a cliff in the fog Dumping nails on the road of life

8 A small change in mean can lead to a large increase in extremes 8

9 sample The IPCC Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation

10 Increasing vulnerability, exposure, or severity and frequency of climate events increases disaster risk Disaster risk management and climate change adaptation can influence the degree to which extreme events translate into impacts and disasters 10

11 Special challenges of climate change Gradual, delayed onset Emerges against a variable background Permanent impacts Global, differentiated impacts Contrasting historical and future responsibility Contrasting responsibility and vulnerability

12 When is it time to act? When the science is certain When risk > cost of acting When risk is meaningful When comparative advantage is real When we know enough to make good decisions

13 Why should we care in California? Global citizens Economic opportunities Social teleconnections Water resources Wildfire Sea level Heat waves Biodiversity Iconic assets

14 A changing climate leads to changes in extreme weather and climate events 14

15 Conflict: ENSO Hsiang et al. Nature 2011

16 Projections for California -- dramatic warming by 2100 Low emissions Business as usual emissions Winter ºF Summer Hayhoe et al. PNAS (2004)

17 Snowpack in the West Less spring snow = less water for summer Decreased snowfall AND increased melting Mote et al. Bulletin AMS 2005 Change from 1950 to 1997 Observations at 824 stations

18 Future climate change Global average temperature has increased by about 1ºF over the last century Warming over the 21 st century could be ºF (IPCC, 2001) Future emissions make a big difference in future climate Huge difference in impacts between the these extremes LOW California snowpack in the late 21 st century BAU 100% 80 Business as usual emissions: 11% remains 60 Low emissions: 27% remains 40 Hayhoe et al PNAS. 20 0

19 Wildfire in the west Increase in area burned annually for each 1 C increase in temperature An exceedingly sensitive system National Research Council, Climate Stabilization Targets, 2010 Based on Littell et al., Ecological Applications, 2009

20 Sea level: A question of extremes Cayan et al. Climatic Change 2009

21 Flood risk in the Sacramento Delta Burton and Cutter, Natural Hazards Review 2008

22 Heat related mortality Average annual excess deaths Excess heat-related deaths Los Angeles Current Low Sensitivity/Low Emissions Low Sensitivity/High Emissions Medium Sensitivity/Low Emissions Medium Sensitivity/High Emissions Based on local mortality statistics for temps above 34ºC Watts & Kalkstein Ann. Assoc. Am. Geog.

23 Euphydryas editha bayensis Centaurea solstitialis Ochrotona princeps Angel Watkins, US Forest Service, 2007

24 USA Today: What if it is a big hoax

25 No regrets/low risk options Preparedness for current variability Biodiversity conservation Energy efficiency Energy independence Clean technology Decreased air pollution Vibrant urban and rural communities Delay until 2051 the wealth the world could have had in 2050.