In my thread "Will You Vote Republican," somebody who goes by Vigilante sent me a reply that seems to refute the whole human caused global warming thing. But I thought my reply is something that you would all like to weigh in on.
Well, some of us anyway.
Each year, all the volcanoes on earth put out an estimated 200 MILLION tons of CO2. Though some of this of course goes directly into the oceans. Humans on the other hand are responsible for an estimated 26.8 BILLION tons per year. Also, anybody who wishes to can look up a graph of the amount of CO2 humans have put out since the beginning of the industrial revolution. Lately, human generated CO2 appears to be going up at a rate that is beyond exponential. There is a good chance that temperatures will follow suit.
The problem you will find around here is that the deniers here will argue that no one can prove the greenhouse effect is real. This takes a number of variations. We have those who think CO2 causes some warming but it is a trivial component of the observed warming and essentially irrelevant. We have others who continue to claim that no experiment has ever shown CO2 causing a temperature increase despite having been shown text and video describing several experiments that, of course, show precisely that. We have others who've begun to argue that adding CO2 to the atmosphere actually causes the planet to cool.
We get analogous arguments about the acidification of the oceans: that the amount of CO2 humans have released couldn't possibly have had a significant effect on the ocean's pH to those that argue that CO2 in solution forms not carbonic acid but sodium bicarbonate.
This past summer, temperatures were fairly cool around where I live. But from what I have seen, if there are cooler temperatures in one area, it means that temperatures are hotter in another area of the earth.
It's really not possible to judge the Earth's climate from an isolated location for a limited amount of time.
I have a sister who is a human caused global warming denier. She points that in the far distant past, atmospheric CO2 levels were much higher than they are now. Which is true. Around one hundred million years ago or so, they were much higher. Apparently because of the breakup of the continents, things have been cooling down over a long time. Causing many ice ages. But as far as I have seen, this isn't something that happened a very long time ago. When global CO2 levels were much higher. We are in uncharted territory. No doubt there is much more methane in places like frozen tundra or shallow seas than there was in the far past. And methane is 20 times better at causing global warming than CO2. Just how much warming will it take for that to start getting released in ever greater quantity. It's hard to say. But there is one thing I know for sure. Most people don't really care what happens. As long as it happens to someone else.
I'm not sure what all that was supposed to mean. But... the predominant cause of warming and cooling in the Earth's geological past has been the Milankovitch orbital cycles. When changes in the amount of sunlight the Earth receives take place, it tends to change the amount of CO2 in the atmosphere. That has shown itself, at least in studies of the last 22,000 years, to enhance warming and cooling periods. Warming is begun initially by orbital changes but after only a few hundred years, greenhouse warming from increased CO2 becomes the dominant driver. And the extremes in the Earth's past - all of the non-catastrophic changes - took place immensely more slowly than they are taking place today. The same changes in CO2 levels and temperatures that humans have seen in the last 150 years could easily have taken 150,000 years in the pre-human past.