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WHAT IS CLIMATE CHANGE? Anthony R.E. Sinclair Biology 302, Section 201. Climate change refers to the increase in global temperature due to the release of gases from Human population increase and its activities. THE INTERCONNECTED EFFECTS OF HUMANS ON THE WORLD. The first evidence.
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WHAT IS CLIMATE CHANGE?Anthony R.E. SinclairBiology 302, Section 201 Climate change refers to the increase in global temperature due to the release of gases from Human population increase and its activities
THE INTERCONNECTED EFFECTS OF HUMANS ON THE WORLD
The first evidence Concentration of CO2 emissions in Hawaii Krebs Fig. 28.9; p592
HEAT RETENTION The gases help to trap heat from the sun instead of reflecting it away from Earth Results in an increase of air temperature at a rate that is not seen historically This reflects the effects of humans
GLOBAL TEMPERATURE – put it into perspective Historically global temperature has varied considerably 1. Over the past 1 billion years there is a 300 M year hot-cold cycle 2. Over past 400,000 years there are clear fluctuations that are also seen in shorter time sales of 10,000 years
GREENHOUSE – ICEHOUSE EPISODES Covering 1 billion years
100 200 300 400 TEMPERATURE CHANGE OVER 400,000 YEARS –from ocean cores 100 100 100 100 100 100 200 200 200 200 200 300 300 300 300 400 400 400 An estimate of temperature variations over last 400,000 years, obtained by comparing O2 isotope ratios in fossils taken from ocean cores in the Caribbean. Dashed line is the ratio from 100,000 years ago.
Average temperature 1902-1980 Next Fig. Note the sudden increase at present time
Average temperature 1902-1980 Next Fig.
Estimated mean global surface temperatures, 1860 – 1990, relative to 1940 1940
TEMPERATURE will lead to • +3C at equator, and +5-8C at poles • 0.6C increase in world temperatures since 1900 • 2nd warmest year historically was 1997; warmest was 1998
Coal burning power plants put 1. particles into the air 2. Carbon dioxide into air
BURNING UNWANTED GAS AT OIL RIGS
Vehicle exhaust fumes
CARBON CYCLING • (Krebs p590-600) • CO2 is in the atmosphere at 0.03% • 99% locked up in coal, oil, limestone, chalk etc. Human activity produces about 5-10% of natural emissions • some 93% due to fossil fuels, 7% from deforestation • before industrial revolution280ppm • currently about 355ppm • projected to be 700ppm by 2100 (unless rather profound change to human activities)
DEFORESTATION REDUCES GLOBAL ABILITY TO ABSORB CO2
WHO IS PRODUCING CO2? • US Energy Information Admin forecast that world emissions will increase by 54% above 1990 levels by 2015, or x2 CO2 in about 40 years (2030) • Canada produces only 2% of global greenhouse emissions (but with 0.5% of world’s population) • From 1960–1990, Canadian emissions increased by 250% • GCM (General Circulation Models) predict x2 CO2 = increase 1.3 to 4.5C
TOP 10 COUNTRIES CO2 EMISSIONS TOTAL OUTPUT (M tonnes/yr) IN 2000 CO2 EMISSIONS % change 1990-2000 Source World Res Inst 2008)
CLIMATE CHANGE: CAUSES 1. Power stations – coal, gas 2. Vehicles 3. Fires – homes & forest 4. Decomposition – garbage 5. Plant respiration
CLIMATE CHANGE: CONSEQUENCES 1. PHYSICAL 2. BIOLOGICAL 3. ECONOMIC - SOCIAL
CLIMATE CHANGE: CONSEQUENCES 1. PHYSICAL EFFECTS
GLOBAL ICE MELT • Ice cap is melting faster than predicted in Antarctica • retreat of glaciers worldwide • N-ward movement of permafrost in the Mackenzie River Basin
SEA LEVEL RISE We already see a +25cm sea level rise in past 100 years
New study says sea levels rising due to a warming ocean – not melting ice
VANCOUVER -Richmond will be flooded
Glacial ice melt over 76 years of the Upsala glacier in Patagonia, Argentina
WORLD GLACIERS LOSING ICE THICKNESS
HUBBARD GLACIER, ALASKA – warmer climate has caused surges –
Which blocked the bay, created a lake and threatened a town, • as in 1993
Alaska melting permafrost is causing soil erosion
HURRICANE KATRINA OVER NEW ORLEANS - Warmer climate puts more energy into storms
PHYSICAL EFFECTS 1. Melting of ice caps, 2. Rise in sea level – more water + warmer water 3. Retreat of glaciers 4. Melting of permafrost in Arctic 5. More violent stroms
CLIMATE CHANGE: CONSEQUENCES 2. BIOLOGICAL EFFECTS