Warmer Oceans result in coral bleaching and the death of coral reefs support more powerful hurricanes 32 Global Ocean and Atmosphere Temperature Trends Compared 33
Warmer Oceans and Coral Bleaching 1997-1998 34 Warmer Oceans and Coral Bleaching 35
Hurricane Energy Source Observed sea surface temperature and predicted and observed minimum central pressure at sea level in tropical cyclones. 36 Hurricane Katrina and SST 37
Hurricane Rita and SST 38 Warmer Oceans: Stronger Tropical Storms Annual mean sea surface temperature and hurricane intensity index (strength times duration). 39
Warmer Oceans and Tropical Storms Warmer oceans support more powerful hurricanes. Photo above is of the first hurricane ever to strike Brazil. 40 Distribution of Extreme Rainfall Events Percent of the continental USA with a much above normal proportion of total annual precipitation from 1-day extreme events (more than 2 inches or 50.8mm) 41
Sea-Level Rise Observations of global sea level rise are very difficult to make because of the vertical motion of the land in many parts of the world, and the small signal in the data. 42 Sea-Level Rise Global average sea level rose ~0.2 m during 20 th century Warmer temperatures cause sea level rise because of Thermal expansion Melting of continental and Greenland glacier ice 43
Sea-Level Rise Satellite altimetry record indicates ~3 mm per year of sea level rise over the past decade. 44 Global Warming Global Warming is linked to population and industrialization. Global trend in energy consumption. 45
Greenhouse Gas Concentrations Concentrations have increased dramatically since Industrial Revolution 46 2001 Value = 371 0.45% per year increase recently 35% increase Since Industrial Revolution Pre-industrial Value = 275 Mauna Loa Greenland Ice Core 47
CO2 Gas Concentrations Famous carbon dioxide data from Mauna Loa, Hawaii. 48 Data from Petit,et al. (1999), and GISS (2003) Previous Warm Periods Previous 2000 Glacial 1990 Periods 1980 1970 1960 1750 Vostok, Antarctica Ice Core 49
50 The last 160,000 years (from ice cores) and the next 100 years Temperature difference from now C 10 0 CO 2 in 2100 (with business as usual) Double pre-industrial CO 2 Lowest possible CO 2 stabilisation level by 2100 CO 2 now 700 600 500 400 300 200 CO 2 concentration (ppmv) 10 160 120 80 40 Now Time (thousands of years) 100 51
What is causing the CO2 increase in the Atmosphere? A: Fossil Fuel Burning: Coal, Oil and Natural Gas. How do we know that? Circumstantial Evidence of timing of increase with rise of fossil fuel use. Smoking gun evidence of isotopic studies. 52 The Carbon Isotope Evidence Carbon 14 is produced in the atmosphere by cosmic rays. C14 is incorporated into CO2 and taken up in plants during photosynthesis Dead plant matter is used to make Fossil Fuels C14 is radioactive and decays with a half life of ~5,700 years Since the plant matter in fossil carbon fuels is millions of years old, it contains no C14. 53
The Carbon 14 Evidence C14 is decreasing with time in the atmosphere at about the right rate to be explained by fossil fuel burning. This is strong evidence that the new carbon in the atmosphere in the form of CO2 is coming from fossil fuel burning. 54 Greenhouse Gas Emitters 55
Future Global Warming Modeling Climate Change 56 The Climate System is very complex with many parts 57
Modeling Climate Change Modeling climate change means modeling the water cycle. 58 Modeling Climate Change by adding complexity 59
Modeling Climate Change by adding resolution 60 Modeling Climate Change requires the fastest super computers 61
Modeling Climate Change requires the fastest super computers Modeling climate change means modeling the ocean circulation. 62 Modeling Climate Change requires the fastest super computers 63
Variations of the Earth s surface temperature; 1000 to 2100 Future temperature trends for different responses to global warming. 64 Future Global Warming is Non- Uniform Change in surface temperatures due to a doubling of CO 2 concentrations and anthropogenic sulfur emissions Most land areas will warm faster than the global average 65
Future Global Warming Non- Uniform Most land areas and high latitudes will warm faster than the global average, resulting in melting and thinning of arctic ice sheets. 66 Warmer Earth means more Droughts and Floods Warmer land means more droughts, hot air holds more moisture. Warmer ocean means more evaporation and more precipitation/floods. Precipitation increases expected over northern mid- to high latitudes. Regional decreases and increases at low latitudes Larger year to year variations in precipitation 67
Modeling Sea Level Rise Thermal expansion of seas and melting of land ice expected to cause sea level rise of 0.1-0.9 m rise expected by 2100 depending on societies response to global warming. 68 Sea-Level Rise Should Greenland s Glaciers melt, it would result in a 20-meter rise in sea level. 69
Florida? 70 Anthropogenic Climate Change will Persist for a Long Time Gas CO2 CH4 N2O CFC s Atmospheric lifetime 50-200 yr 12 120 50-300 71
Summary: Climate Change Earth s climate was warmer than now during most of its history (e.g., last billion years). Ice ages and cooler average temperature for past 2 million years Forcing for climate change includes astronomical and internal factors. Climate change research is complex due to many components of climate system and feedback mechanisms. Compelling evidence for global warming during past 100 years is consistent with increase of green house gases from burning fossil fuels. 72 Global Warming Some Implications Under conditions of global warming, the troposphere will warm, the stratosphere will cool, and ocean surface temperatures and sea level will rise. 73
Species Impacts Each 1 C of warming will shift temperature zones by about 100 miles northward (or 500 feet in elevation). Many plant and animal species will be unable to migrate fast enough to find suitable habitats Natural or man-made barriers may block natural migration An increase of 3 C could threaten 7-11% of North America s plant species. Northern limits of many birds strongly associated with climate. Loss of cold-water fish habitat of 1.7-2.3 million acres by 2060. 74 Climate and Energy Policy 75
Impact of Stabilizing CO2 76 Oil Discovery vs Production We now are discovering fewer than 8 billion barrels annually compared with the 28 billion barrels we consume. Suppose that a 200 billion-barrel bonanza is found, an amount of oil equal to all that the United States will ever produce. At our projected rate of consumption, the 200 billion barrels would be burned in seven years! Oil producers in 1000 barrels per day 77
Oil Production vs Consumption History of US Oil Production US consumption exceeds production. An increasingly hostile group of Middle Eastern nations are in control. 78 Global Oil Past and Projected Production Experts agree, oil prices will rise significantly in the future as production begins to drop. 79
Global Oil Past and Projected Production Pessimistic view vs the optimistic view. 80 Possible responses to climate change threat Reduce greenhouse gas emissions Global approach required Assistance to developing world key Economic costs not unmanageable Economists suggest a 20% reduction in GHG emissions would require a GDP cost of <1% (loss of 6 months economic growth or less) and indicate the costs may even be negative Past air pollution regulations suggest costs are often much lower than claimed by industry (e.g., catalytic converters, CFC elimination, SO2 emissions reductions) Engineer to mitigate possible climate consequences e.g., sea walls, agricultural adaptation, 81
Strategies to Control Warming Stabilize world population Initiate a no-coal world energy strategy Vastly enhance renewable energy dependence Institute strong energy conservation Develop treaties strongly controlling greenhouse gases Discover counter-greenhouse technologies 82 Strategies to Live With Warming Improve irrigation efficiency Develop new sources of irrigation water Stop deforestation increase forestry plant trees Conserve soil prevent erosion Grow salt tolerant food plants and expand aqua culture Plan for increased ocean height 83
Energy Conservation According to a NASA study, we can decrease CO 2 emissions by 40% by doing the following five things. 1. 30% increase in auto fuel efficiency. (For every gallon of gas burned 25 pounds of CO 2 are released into the atmosphere.) 2. Use compact fluorescent bulbs 3. More efficient motors 4. Tougher standards for refrigerators and dishwashers 5. Development alternative renewable energy sources. 84 Energy Conservation Promote mass transit where appropriate. Promote electric car technology. Expand use of natural gas (cleaner fuel). Improve quality of gas lines, especially in Eastern Europe. Recover methane from landfills. Promote co-generation technologies - e.g., recovery of waste heat; produce electricity as a by-product of production. Improve manufacturing techniques - e.g., electronic inventories; automated manufacturing where inventories are eliminated. Promote alternative energy-wind and solar power - local energy sources eliminate transmission loss. Strengthen efficiency standards throughout the economy. Improve building codes: insulation, improve lighting and appliance efficiencies, promote use of passive solar. 85
In Hawaii Gasoline in Hawaii is not only expensive, the oil consumed represents an export of cash from our economy that literally just goes up in smoke. Ethanol from sugar cane. Because of the energy return from burning the residue of sugar cane crushing to generate heat for processing the sugar into ethanol and to generate electricity, the net fossil fuel consumption is actually negative! Hawaii's pre-1985 sugar production on 180,000 acres could have produced enough ethanol to cut gasoline consumption currently by 30 percent. Wind energy. The trade winds provide reliable source of energy. Wind farms must located in areas of enhanced winds, but with a minimum of terrain-induced turbulence, which causes wind turbines to wear out faster. Solar energy sources. Photovoltaic cells are becoming more efficient and economical. Geothermal energy sources Wave and tidal energy sources 86 Questions? 87