Overview of Climate Change and Impacts

Transcription

1 Overview of Climate Change and Impacts Michael J. Prather Fred Kavli Chair of Earth System Science Director, UC Irvine Environment Institute University of California, Irvine Jefferson Science Fellow, U.S. State Department, 2005/6 26 Jan 2008

2 to everything there is a season, Red River Freeze Dates getting later no freeze Grand Traverse Bay Red River Thaw Dates coming earlier

3 to everything there is a season, 1996 Chacaltaya Glacier, Bolivia 2005

4 to everything there is a season,? and Spring is happening sooner but not everywhere

5 to everything there is a season,

6 but The Times They Are A-Changin Come gather 'round people Wherever you roam And admit that the waters Around you have grown And accept it that soon You'll be drenched to the bone. If your time to you Is worth savin' Then you better start swimmin' Or you'll sink like a stone For the times they are a-changin. sea level rise B. Dylan 1963

7 the ocean is warming and sea level is rising! 2007? software bug in floats? 2008 corrected (black line) 2007 IPCC AR4

8 What is the IPCC? Bert Bolin (d. 30 Dec 2007) IPCC 1990: 1 st Assessment Report Sir John Houghton IPCC TAR 2001: 3 rd Assessment Report IPCC AR4 2007: 4 th Assessment Report

9 What is the IPCC? more than just the Summary for Policy Makers 1000 s of scientists publishing climate-related research

10 What is CLIMATE? We have sun, earth, and atmosphere, so we have weather! Harris Telemacher (Steve Martin) in LA Story CLIMATE = statistics of atmospheric weather + oceans + ecosystems +... Both Weather and Climate have internal variability like El Nino. This precludes definitive predictions, and leads naturally to a statistical approach in forecasts, e.g., 80% chance of rain tomorrow 84% chance of 2 C global warming by 2100 Climate also responds to external forcing that alters the heat balance Stratospheric aerosols from Mt. Pinatubo volcano cooled the Earth Greenhouse gases trap heat and warm the Earth Climate tries to the balance the radiative forcing (heating vs. cooling)

11 Ice Age Climates: the Pleistocene Last interglacial Current warm period Proxy Last Ice Age

12 Ice Ages: the Pleistocene measurements from ice cores show correlations between the greenhouse gases and temperatures and size of glaciers N2O CO2 CH4 Temperature proxy Ice Volume proxy 2007 IPCC AR4 Thousands of Years before 2005

13 The Holocene the last 11,000 yr of relatively stable climate 11,000 yr 2007 IPCC AR4

14 The Anthropocene: the atmosphere Agriculture, Industry & Land-use change have dramatically changed change the global atmosphere: increasing both greenhouse gases (CO2, CH4, N2O) and sulfate aerosols IPCC TAR COOLING WARMING

15 The Anthropocene: the radiative imbalance Greenhouse gases trap the Earth s heat and warm the planet. Aerosols and their interactions with clouds reflect sunlight and cool. The net heat imbalance is called Radiative Forcing (RF, in W m -2 ) COOLING WARMING 2001 IPCC TAR

16 What else is happening to the climate? 2007 IPCC AR4 Global average sea level rose at an average rate of 1.8 mm per year over 1961 to The rate was faster over 1993 to 2003, about 3.1 mm per year. Whether the faster rate for 1993 to 2003 reflects decadal variability or an increase in the longer term trend is unclear.

17 The Anthropocene: mean surface temperatures warm Climate science sees sustained warming 2009 NASA/GISS

18 The Anthropocene: mean surface temperatures warm 2008 but look at year 2008 amateurs argue that we are now cooling 2009 NASA/GISS cooling!!!

19 The Anthropocene: mean surface temperatures warm 2008 add year NASA/GISS warming

20 but not everywhere, not uniformly, and not regularly 2009 NASA/GISS

21 (2010) Global variability vs. Local (USA)

22 The Ice Ages: can we calculate global cooling? YES ICE-AGE Radiative Forcing < 0 Note: CO 2 and CH 4 are the driving forces here. Note: CO 2 and CH 4 are positive feedbacks here IPCC AR4

23 Detection & Attribution: Did it change? What caused it? Global mean surface temperature anomalies ( C) from 1900 to 2005 from observations (black) from AOGCM* simulations forced with natural forcings only (blue, 19 simulations w/ 5 models) from AOGCM simulations forced with both anthropogenic and natural forcings (red, 58 simulations w/ 14 models) *AOGCM = atmosphere+ocean climate models 2007 IPCC AR4

24 Greenhouse gas signal seen on every continent except Antarctica PINK (with GHGases) matches BLACK (obs.) 2007 IPCC AR4

25 It is really just the sun changing climate. It is all done with cosmic rays.

26 (2010)

27 (2010) climate change predicted similar to ENSO

28

29 Climate Prediction: Climate Normals are the daily, monthly & annual 30-year climate averages ** U.S. Normals ~8,000 stations Main Parameters Temperature (max, min, mean) Heating & Cooling Degree Days Spring/Fall Freeze dates; growing season Precipitation (usually liquid equivalent; sometimes snow) Occasionally: clouds, sea level pressure, RH, others ** Tom Karl DOS/INR Climate Workshop June 2007 WMO Recommendation Countries update normals every 10 years Current period Next scheduled period: for use in 2010s

30 but climate is changing: ACTUALS minus NORMALS ( C) January Min. Temperature Most areas in continental U.S are now 3 7 degrees warmer during winters nights Florida, S. Georgia now 2 4 degrees cooler July Max. Temperature Most of Western U.S. now 3-7 degrees warmer during summer days Some Parts of South U.S. cooler T. Karl, DOS/INR Climate Workshop, C to +7 C

31 predicting the next decade from the climate normals unpredictable 2007 IPCC AR4

32 Katrina 28 Aug 2005 extreme climate

33 Rita 25 Sep 2005

34 Wilma 19 Oct 2005** 185 mph winds three times in one summer??

35 Heat Waves: 2003 October 9, Copyright 2003 Earth Policy Institute RECORD HEAT WAVE IN EUROPE TAKES 35,000 LIVES Far Greater Losses May Lie Ahead Janet Larsen A record heat wave scorched Europe in August 2003, claiming an estimated 35,000 lives. In France alone, 14,802 people died from the searing temperatures more than 19 times the death toll from the SARS epidemic worldwide. In the worst heat spell in decades, temperatures in France soared to 104 degrees Fahrenheit (40 degrees Celsius) and remained unusually high for two weeks.

36 climatology of heat waves 2003 was an extremely rare event in terms of climate statistics, a 5.4-sigma extreme, a one-in-a-thousand year event IPCC AR4

37 predicting the next heat waves without anthropogenic forcing: every 1000 yrs with anthropogenic forcing: every 250 yrs 2007 IPCC AR4

38 Greenhouse Gas Emissions the cause Sector GHG Emissions 2007 IPCC AR4

39 2007 IPCC AR4 Who s to blame?

40 A Climate Forecast or a Climate Projection? 2007 IPCC AR4

41 A Climate Forecast uncertainty in positive climate feedbacks in a warmer world A Climate Projection 2007 IPCC AR4

42 2007 IPCC AR4 For the next 30 years, we should be able to forecast climate change with current knowledge. ** For the next 90 years, we can only project climate change based on our ability to mitigate GHGases. ** with improved climate observing systems, decadal initializations,.

43 2013 IPCC AR5

44 California Adaptation (2009)