absorption, anthropogenic global warming, atmosphere, carbon, climate, climate change, climate denier, CO2, emissions, environment, evaporation, glacial period, glaciation, greenhouse gas, industrialisation, IPCC, obliquity, radiation, scientists, solar activity, temperatures, United Nations, volcanic activity, water vapour
I was in England, my birthplace, for three weeks and basically offline. It was good to see the place again before it goes down the Brexit gurgler. Meanwhile, climate deniers are still busily trying to deny reality: that we have serious anthropogenic global warming and it’s our doing. The kids have got it right with their marches even if the deniers haven’t.
A guy on a Facebook page here is Australia was going on about the ‘evil’ UN, all sorts of nonsense about CO2, and how our government is guilty of child abuse as our schools don’t teach climate denial. I fired off the following four replies to his rubbish.
–Climate change was natural until the industrial age. Now it’s main influence is our CO2 emissions. We are releasing twice as much CO2 as the natural environment can absorb, thus the build up of CO2 and rapid increase in temperatures, at least 10 times faster than coming out of the last glacial period. Yes, CO2 was much higher in the past such as 500 million years ago but solar activity was 4% lower. CO2 levels were falling due to carbon being sucked into the ocean and also due to mountain building and rock weathering. Because of this and the lower solar activity, the CO2 threshold for glaciation was about 3000 ppm.
–CO2 has a greater effect than water vapour on temperatures. Water vapour is in the atmosphere a short time. CO2 can last hundreds or even thousands of years. Also, the extra water vapour in the atmosphere is due to the extra warmth caused by more CO2. Temperatures peaked around 5000-10000 years ago after the glacial period and overall gradually fell after that, until last century. They have shot up with industrialisation. They are supposed to be still gradually decreasing as we head to the next glacial period in several tens of thousands of years time as earth’s obliquity gradually decreases.
–Your understanding of CO2 is lacking. Yes, CO2 absorbs virtually all the heat it can. It’s also true that extra CO2 won’t absorb too much more heat at the earth’s surface. But CO2 also radiates heat and does this in random directions including back to earth. Higher up, the atmosphere is much thinner and unsaturated although there is still plenty of CO2 up there but not much water vapour. This high altitude CO2 absorbs some of the heat that would otherwise have been heading for space and radiates some of it back to the surface. For a fuller explanation, see http://www.realclimate.org/…/a-saturated-gassy-argument/. Water vapour is also a greenhouse gas. Extra CO2 causes higher temperatures which means more evaporation, thus there is more water vapour in the air too. There is about 4% more water vapour than 40 years ago.
Solar activity has been falling since about 1960 and is not the cause of the higher temperatures we’ve seen in recent decades. Nor is volcanic activity which is low these days by historical standards. Besides, our emissions are currently about 100 times volcanic emissions over a year.
Yes, CO2 is essential and all that. Problem at the moment is, as I said before, we are releasing about twice as much CO2 as the environment can absorb naturally so it builds up in the atmosphere causing temperatures to increase.
–Virtually every country in the world is a member of the UN. Climate change is a small part of its work. Most of its work is in the areas of peace, security, human rights, aid and development. It became involved in environmental issues in 1972. It set up the IPCC in 1988 to monitor climate change research as many scientists had found plenty of evidence for anthropogenic global warming by then and AGW came to be regarded as a worldwide issue. From 1997, the IPCC set emissions reductions targets for each country. The IPCC doesn’t research or monitor climate change itself but assesses the literature. Thousands of scientists are involved in this. The scientists write and review reports and get consensus from governments of countries participating in this process, which is about 120 of them. It has nothing to do with the “rich and elite”. And no one is attacking kids although the kids (and the scientists) seem to know a lot more about climate science than deniers.