Editor:
Several letters recently published in The Herald have said current signs of global warming are part of a natural cycle. Further they say we should not take any precautionary steps to reduce our CO2 emissions because they might be too expensive. The warming we're seeing is NOT part of a natural cycle but is the result of an increase of CO2 and other greenhouse gases that humans have put in the atmosphere over the past 150 years. Glaciers are retreating, arctic ice is disappearing, methane is bubbling up from the permafrost, and islands are submerging.
How do we know the cause is CO2? First, CO2 concentration has increased from 284 ppm (parts per million) from the early 1800s to 387 ppm currently. Second, based on research done over 100 years ago, CO2 in the atmosphere is a greenhouse gas that traps heat. The planet Venus, for example, has vastly more CO2 in its atmosphere than Earth. Its surface temperature is 467° C, not because it's closer to the Sun, but because of the CO2.
Two main factors in global temperature are the sun and CO2. If we only use fluctuations of solar radiation (the sun) over the past 50 years, we are just like someone who tries to predict a child's height based only on the height of one parent. However, if we use solar radiation and CO2 levels over the past 50 years, we get better results. The test of accuracy of our prediction is to compare the actual temperature record with the results of prediction models. Climate scientists have found that their set of predicted temperatures are most accurate if they include CO2 and solar radiation in their models. If they don't include CO2, their prediction runs are inaccurate.
Global warming is real and it's urgent to take steps immediately to reduce our use of fossil fuels. It's nothing short of insane to listen to those who say it's a natural cycle and we can continue to spew CO2 into the atmosphere.
A final note: 1970's ice age predictions were predominantly media based with the majority of scientific papers (42 to 7) predicting warming (http://tinyurl.com/2vdj8u). We've had the information for years. At this point, there should be no debate, only urgently needed action.
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Mark Sandilands
Lethbridge
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