If we continue with business as usual as 'skeptics' want, how much will the planet warm?
A fairly popular global warming contrarian argument (particularly with a certain CO2 Expeller) is that the planet won't warm very much over the next century, so we don't have to take serious steps to reduce carbon emissions.
The IPCC modeled various scenarios in AR4, including A2 (moderate economic growth and some adoption of alternative and renewable energy sources) and B1 (a major move away from fossil fuels). I think it's fair to say that A2 is what most 'skeptics' propose (take small steps to slowly move away from fossil fuels), while B1 is more what proponents propose (take major steps to quickly move away from fossil fuels). Currently our CO2 emissions are actually on pace with scenario A1F1 - high economic growth and continued reliance on fossil fuels.
Scenario B1 results in atmospheric CO2 around 600 ppm in 2100, and a warming of about 1.8°C between 2000 and 2100. Scenario A2 is 850 ppm CO2 and 3.4°C warming over the next century. http://www.skepticalscience.com/monckton-myth-3-linear-warming.html
In other words, in order to keep the rate of warming over the 21st century as low as it is now, we need to take major steps to move away from fossil fuels, as AGW proponents propose.
If we continue with business as usual as 'skeptics' want, how much do you think the planet warm?
Anonymous2011-01-17T14:37:38Z
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going by your fig.2, over 6 degrees. it will be A1F1 until at least 2050, and the forcing will be at the top of the ipcc range. then the arctic methane and ice feedbacks really kick in....
What this skeptic wants is to develop transportation solutions and energy conservation that will ease the energy crisis. What I don't want is taxes and energy-cost increases that fund carbon trading "schemes" (read scams) and discredited climatologists. The increases in carbon dioxide can be enterpreted as nothing less than a moderating force in the environment, with major benefits to plant growth on the planet. The tree-ring data that provided the foundation for the IPCC models correlate with carbon dioxide. Trees grow better when carbon dioxide approaches 1,000 ppm. It doesn't necessarily correlate to a higher temperature. Their hypothesis is flawed, evident in current temperature decline.
Trick question. Nice try Dana. The real Skeptical answer is, "We don't know." And anybody with a brain bigger than their ego knows this is true. We know that doubling CO2 concentration should lead to about a 1 C increase in temperature.
We don't know how all the other forcings work. This winter in the UK is evidence of that. The Argo buoys finding the oceans are cooling slightly is evidence of that. When a guy with a laptop can beat the Met predicting the weather (see link), it's clear that conventional wisdom (groupthink) among climatologists is flat wrong. Look Dana, your guys missed the last two winters and the summer before. And we are supposed to trust their predictions for 90 years in the future.
When somebody with a laptop and public information can beat a whole group of scientists and their supercomputers, something is wrong. I have NO confidence in their end of the century predictions.
Now give me four TD's from you and your aliases and explain why the Met can't figure out if the upcoming winter will be hotter or cooler than average.
The ultimate scenario, business as usual, full steam ahead, frack everybody, would likely lead to about a 10C or 18F increase in global average temperatures by the time things are done. Your other respondents have pointed out things like tar sands and oil shale, so figured I'd throw in hydro-fracking, which devastates underground areas. Coupled with the surface ecological damage from our current mining practices as we get every drop of hydrocarbons we can wring out of the earth, every puff of natural gas, we will have set ourselves up for a range of possibilities from total social and technological change to effective collapse of the current civilization. I'd estimate that I might be off 2-3C for the low side, and 5-7 or 8C for the high side, giving a range of 7-18C for eventual warming, roughly 12-25F, and I strongly suspect even the low end would prove slowly catastrophic, as weather disaster after weather disaster unfolds, battering an ever-weakening civilization running on ever-diminishing sources of power.
For this prediction, I will be called an alarmist of the worst sort. But what was asked was best guess at a worst-case scenario. There's no point in soft-pedaling a slow Armageddon.
Unfortunately, these people think that 1.8°C is a minor change. On a global scale, that is most definitely not a "minor" thing. I'm guessing that the temperature will rise 2.5-3 degrees.
Whether stopping the use of fossil fuels will do anything is debatable, apparently.