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Earth 002 Thursday, February 25th, 1999
Lecture notes: THE FUTURE: GLOBAL WARMING CO2 Levels Since 1958, there has been a steady increase in the levels of CO2 in our atmosphere There is no doubt that these increases have been brought about by human activity 80% of the increased CO2 is the result of burning fossil fuels 20% of it comes from deforestation
The change in CO2 levels is so potent that humans can change the composition of the atmosphere The last ice age showed 180ppm CO2 in the atmosphere...this is expected to increase quickly in the future Expectations If we keep putting more CO2 into the atmosphere, we expect the earth to be getting warmer and warmer A big global warming pattern was seen in the temperature history of the last century The temperature change over the last century is only 8/10 of a degree This temperature change predicts alot of natural variability...CO2 increases, Temperature increases What's the cause of this warming trend? 1. People observe things in different ways (ex. even temperatures are recorder more often than odd tempertaures...10,12,14 instead of 11,13,15) 2. Instruments are changing and so are the places where the temperatures are being taken Urban Heat Island-temperature is increasing as a result
of the growth of cities Scientists comb through these observations and kick out the ones coming form big cities or new thermometers Precipitation Pennsylvania is now much wetter than it was at the beginning of the century Rainfall is now coming in bigger events (larger rainfalls) Global Future Models predict that having two times the CO2 we have now that the climate will be 8-10 degrees warmer. This warmth occurs at areas with high latitude With four times the CO2, the temperature would increase by 20 degrees If these models are correct, climate change will be a significant factor in our lives Bottom Line Big climate change-->Significant factor in our future ICE-on scale of 1000's years...if ice is capable of changing predictions, we're in trouble VEGETATION-tree seeds can migrate...Future Climate Models have fixed vegetation Green Slime Model-fixed albedo Large Leaf Model CLOUDS-low clouds-->cooler planet What happens to clouds during periods of global warming? Each prediction model calculates clouds differently (COOL earth-->LOW clouds, WARM earth--> HIGH clouds **Basically, don't believe the climate models...you must personally decide whether or not to take action to better our planet, knowing that these models may err. |
