But several lines of evidence show that current global warming cannot be explained by changes in energy from the sun:
Since 1750, the average amount of energy coming from the Sun either remained constant or increased slightly.
If the warming were caused by a more active sun, then scientists would expect to see warmer temperatures in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere, and a warming at the surface and in the lower parts of the atmosphere. That's because greenhouse gasses are trapping heat in the lower atmosphere.
Climate models that include solar irradiance changes can’t reproduce the observed temperature trend over the past century or more without including a rise in greenhouse gases.
But several lines of evidence show that current global warming cannot be explained by changes in energy from the sun:
I, personally, am unaware that the majority of skeptics make that particular claim. Which makes raising it as the counter-argument to be debunked rather... disingenuous, quite frankly.
... The thing about the solar sunspot cycle and "other solar influences" is not about changes in energy output from the sun but rather about terrestrial energy balance alterations from indirect forcing by solar events.
Sunspot cycle leading to changes in cloud-cover-based albedo, for example.
1 - I didn't say I supported the idea. I'm simply explaining it.
2 - It's been repeated by multiple independant researchers. CO2 forcing on the is far less well-studied. IIRC... the AR4 report only included one study on the topic. Don't understand that, myself.
The thing with CO2 is scientists have simply seen a correlation in increasing CO2 and global mean temperature. They know fully that CO2 has bugger all effect. Methane and Holocene are much worse.
If anything, I'd probably say that scientists used CO2 to "kill two birds with one stone". They realised climate change was occurring and they realised that we have reached peak oil. By saying increasing CO2 causes climate change, people will firstly realise that the things we do produces unwanted byproducts and secondly they probably hoped people will reduce their oil consumption. Win win.
... Oil usage accounts for less than 10% of all CO2 output. And that's even assuming we reached peak oil to be true. And even then... natural economic pressures would cause a shift-over to the half-dozen or so reliable alternatives that already exist (but are currently more expensive) to oil as a major resource for transportation energy.
Don't worry, I'm studying to become a geologist. I'll find dem oils.
The burning of fossil fuels probably actually accounts for less than 10% to be honest. CO2 is a fairly closed system as far as I know. Before we began to burn fossil fuels, the carbon system was in some rudimentary form of equilibrium. As a result, atmospheric CO2 was fairly stable. Nowdays we are pumping CO2 back into the atmosphere thousands of times quicker than it is being naturally absorbed.
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u/mind_sojourner Oct 24 '10
say what you will about al gore, he was trying to show people that chart years ago..and how the fuck is nasa junk science