A commenter on the …andThenTheresPhysics blog has shared a terrific excerpt from a 100-year-old science book by Huxley and Gregory he found in his attic. It’s about the greenhouse effect and how we knew way back then that adding CO2 to the atmosphere would increase the surface temperature on earth.
The atmosphere surrounding the earth may be compared with the glass of a greenhouse, which permits the bright rays of the sun to pass through, but prevents the escape of the dull radiations from the heated surfaces below it. This action is due to the carbon dioxide and water vapour in the air; but as the proportion of the latter varies very considerably, while the quantity of the former is almost the same in the open air everywhere at all seasons, evidently the protective action of carbon dioxide gas is of prime importance. If the proportion of this gas in the atmosphere could be increased, the temperature of the ground and of the air surrounding us would be raised, and if it were to be diminished all parts of the earth would become cooler.
Read the full excerpt here – http://andthentheresphysics.wordpress.com/2015/05/26/guest-post-nothing-new-under-the-sun/
Why have humans wasted so much time over the last decade or two arguing, hoping, pretending it doesn’t exist? It makes me so cross to think we could be in a better place right now had we acted 20 or more years ago. Instead we let people who deny the science shape our world for the worse despite what the science community has known and been telling us for more than 100 years.
We don’t have the luxury of time with this problem. Every second we waste is more CO2 in our atmosphere, more melted ice, and most importantly, it means the reduction we have to make when we finally act will need to be that much greater. We are making the inevitable much harder for ourselves with every year we waste.
If we had started reducing our emissions in 2005, a reduction of 3.5% per year would have led us back to 350ppm of atmospheric CO2 by 2100. This went up to 6% per year in 2013. If we wait until 2020, it’ll be 15% per year. Just a few decades can make an enormous difference.
It is instructive to see how fast atmospheric CO2 declines if fossil fuel emissions are instantly terminated (Fig. 4B). Halting emissions in 2015 causes CO2 to decline to 350 ppm at century’s end (Fig. 4B). A 20 year delay in halting emissions has CO2 returning to 350 ppm at about 2300. With a 40 year delay, CO2 does not return to 350 ppm until after 3000. These results show how difficult it is to get back to 350 ppm if emissions continue to grow for even a few decades.