What Does Science Say About Climate Change?

1. What Does Science Say About Climate Change? Prof. Bill Moomaw Fletcher School, Tufts University November 2004

2. The Earth’s Climate System • Light from the Sun is absorbed by land and water, and is converted to heat. • Some heat is emitted back into space as radiant heat, just as heat is radiated from hot pavement on a July day. • Some of this radiant heat is absorbed by water vapor and clouds, carbon dioxide, methane, nitrous oxide and other trace atmospheric gases. • These gases act like the glass windows in a car creating the “hot car effect.”

3. “Hot Car” Effect and Climate Change Natural Enhanced

4. Brief History of Climate Change Science • 1827 Fourier hypothesizes greenhouse effect • 1860 Tyndal identifies CO2 and water vapor as heat trapping gases • 1896 Arrenhius calculates earth warming from gases and predicts future warming from doubling and quadrupling CO2 • 1930 Calandar shows correlation of temperature and CO2 • 1958 Keeling begins direct measurement of CO2 in atmosphere • 1980 to 2004 evidence accumulates

5. The one constant of climate has been change by natural forces.What is new is that human activities are altering the composition and size of the atmosphere, the face of the land, and the climate system.

6. What natural forces affect the climate system? • Natural fluctuations in the sun’s intensity • The complex motion of the earth around the sun • Volcanic eruptions • Changes in ocean currents • Shorter-term cycles like El Nino

7. What natural forces affect the climate system? • Natural fluctuations in the sun’s intensity • The complex motion of the earth around the sun • Volcanic eruptions • Changes in ocean currents • Shorter-term cycles like El Nino

8. What human activities are affecting climate? • Carbon dioxide from fossil fuels release about 6 billion tons of carbon each year to the atmosphere • Atmospheric carbon dioxide concentrations have increased by nearly 32% • Methane from agriculture, livestock, landfills and industry have increased by 133% • Nitrous oxide from agriculture and industry has increased by 15% • Change in land use and land cover release 1 billion tons of carbon plus other gases

9. What is the evidence for human caused climate change? • Direct measurement of changes in atmospheric composition • Direct measurement of temperatures • Direct measurement of precipitation and other climate indicators • Direct measurement of shifts in species • Paleoclimate records • Climate model verification • Testing models with other planetary climates: Venus, Mars and the moons of Jupiter & Saturn

10. Vostok temperature and CO2

20. Looking to the Future • What will happen to concentrations of climate altering gases such as carbon dioxide if we fail to act? • What will happen to planetary temperatures if we fail to act?

25. Major Indicators of Current Climate Change • Average global temperature has risen by 1o F in past 100 years with high latitude increases of 4o F • Seasons in the US and Europe have shifted by one week in past 50 years • Precipitation patterns are changing • Species are migrating higher and towards the poles

26. Sea level has risen by 6-8” in the past century and is proceeding at a rate of more than an inch a decade More than 95% of world’s glaciers are retreating Polar sea ice has thinned by more than 40% in 30 years, and coastal ice shelves are disintegrating in Antarctica Permafrost is warming and melting rapidly, destroying buildings and roads, and could disrupt Alaska oil pipeline

27. Upsala Glacier Patagonia, Argentina

28. Rhone Glacier Switzerland 1930-2001

29. Pasterze Glacier Austria1875-2004

30. Portage Glacier Alaska1914-2004

31. Recent Findings 1 • Terrence Joyce of Woods Hole Oceanographic Institute argues that the observed slowing of the North Atlantic conveyor could become irreversible if pushed beyond a threshold by climate related changes. • This would cause rapid, major drops in temperatures in Europe and Eastern North America.

32. Link of Climate Change to Security • In February 2004, the Pentagon published a report expressing deep concern of the political and economic destabilization that might accompany abrupt climate change : http://www.ems.org/climate/pentagon-climate-change.pdf • Fortune magazine highlighted this climate change - national security link (Fortune February 2004): http://www • Suddenly, Prof. Wally Broecker’s 1959 doctoral dissertation idea was news!

33. Recent Findings 2 • Satellite measurements of lower atmosphere temperatures have been interpreted as rising less since measurements began in 1979 than land and sea surface trends. • This discrepancy has now been resolved. • Satellite measurements were found to be measuring part of the cooler stratosphere and not just the lower troposphere as was thought. • There is now close agreement with land and sea temperature trends removing another uncertainty. QIANG FU, CELESTE M. JOHANSON, STEPHEN G. WARREN & DIAN J. SEIDEL Nature429, 55–58 (2004); doi:10.1038/nature02524 (May 6, 2004)

34. Recent Findings 3 • The sustained drought in the Sahel region of Africa that began around 1970 has continued • Not only is total rainfall decreased, but what does occur comes in intense downbursts punctuated by drought. • It has been confirmed that this altered weather pattern arises from the warming of sea surface temperature rises in the Indian Ocean. • “If the sea temperature rise comes from global warming, then we are in dire straits.” Alessandra Giannini, Columbia University Science October 13, 2003

35. Recent Findings 4 • Stratospheric ozone loss may be altering climate • The altered amount of ozone shifts the wind patterns around Antarctica with effects that extend much farther. • While the Antarctic peninsula has warmed, the center of the continent has cooled. • The warming appears to be coming from the ocean and leading to the spectacular breakup of state sized ice shelves. Nathan Gillett and David Thompson Science, 10/10/03 • The cooling in the interior appears to be due to the loss of heat through the ozone hole Thompson, D. W. J., and S. Solomon,Science, 296, 895-899, 2002

36. Recent Findings 5 • While human activities release about 7 billion tonnes of carbon as CO2 each year, usually half is absorbed by the ocean, by plants and by soils. • In 2003, CO2 in the atmosphere increased substantially above annual growth rates of the past meaning that less is being absorbed by terrestrial systems and oceans.

37. Recent Finding No. 6 • Antarctic glaciers are accelerating their flow into the sea (where they will accelerate the rise in sea level) since the collapse of the Larsen ice shelf in 2002 • Some glaciers are found to be thinning at twice the rate they were in the 1990s • The loss of the ice shelf is believed to have occurred because of warmer seas R.H. Thomas, et al Science, Sept. 23, 2004

38. Recent Findings 7 • Arctic Climate Impact Assessment released November 8 • “The Arctic is warming much more rapidly than previously known, at nearly twice the rate as the rest of the globe..” • In Alaska, Western Canada, and Eastern Russia average winter temperatures have increased as much as 3-4C (4 to 7F) in the past 50 years, and are projected to rise 4-7C (7-13F) over the next 100 years. • Greenland ice is melting and contains enough melt water to eventually raise sea level by about 7 meters (about 23 feet).

39. So the problem of climate change is of growing concern.What do we do about it?

40. Problem:International agreements are not yet implemented and the US national government favors voluntary actions Solution: Implementation without Ratification

41. Options • Use fossil fuels more efficiently • Move from coal to oil and gas • Extract hydrogen from fossil fuels and store the carbon • Continue to use fossil fuels but capture and store CO2 physically and biologically • Develop efficient market instruments to achieve cost effective energy mix • Utilize other technologies such as nuclear, wind, solar, biomass and geothermal energy

42. Business Opportunities • Investment in renewable energy tripled to $18 billion between 1995 and 2002 • The US once dominated wind, solar and biomass technology, but has fallen behind countries such as Japan, Germany Denmark and Brazil • The IPCC estimates that there is sufficient technology available to reduce global CO2 emissions by 15% in a decade at zero or net negative costs

43. Fossil fuels dominate the production of electricity (64%) followed by hydro and nuclear (17%) and other renewables (2%) • The growth, however, is in the reverse order • Wind 25% • Solar 19% • Hydro 2% • Fossil fuels 0-2%

44. Global Trends in Energy Use 1992 - 2002 World Electricity Generation by Type 2000 Hydro Fossil Fuels

45. Lag Times

46. Innovative Thinking is Needed to Address Climate Change • Now is the time to act, but it requires thinking in new, creative ways • We need to replace talk with action! • There are opportunities for all sectors of industry and to applaud and expand the successful measures of the innovators • There are opportunities to follow the lead of innovative cities like Toronto who began municipal action in 1988

47. Web sites • Photos of glaciers and other evidence of climate change http://www.worldviewofglobalwarming.org/index.html • Summary and synthesis of scientific information http://www.ipcc.ch • Information about Tufts efforts http://www.tufts.edu/tie/tci