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Oh dear. They may have murdered AGW

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Maarten
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  • 4 weeks later...
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A new NASA model which more accurately takes into account the effect of increased atmospheric CO2 on plant growth estimates that doubling CO2 would only increase global temperature by 1.64°C. This is much less than the IPCC AR4 estimate that the temperature change would "likely to be in the range 2 to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C."

(Journal article link)

Correct me if I'm wrong, but doesn't the article omit certain things? They estimated that carbon dioxide intake from plants would decrease the global temperature from .3 Celcuis, making the actual range 1.64-4.2C. I don't know about this report, it seems as though they took the lowest possible number of a range, and presented it as if it was the maximum.

Also, if the temperature raises that much, it could make the weather more tolerable for disease spreading mosquitos. A little temperature increase makes a big difference for them.

http://www.guardian.co.uk/environment/blog/2010/dec/17/register-climate-myths

Edited by Black Wolf
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..Huh? Strange, I can't edit my own post?

by .3 Celcius, not from.

Also, .3 Celcius was a round-up. It's actually .26 celcius that carbon dioxide intake from platns is accounted for

Here's a Chemical Engineer's persepctive on AGW.

http://climaterealists.com/attachments/database/ThermostatCO2HPFeb10.pdf

Edited by Black Wolf
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Quite apart from the issue of the fudged data in the recent instrumental record, looking at past actual temperature variations shows that the worst case projections for global warming aren't even close to what has already happened. The self-playing gif below is one graph that keeps telescoping out to show a greater timeline.

http://wattsupwiththat.files.wordpress.com/2009/12/noaa_gisp2_icecore_anim_hi-def3.gif

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  • 9 months later...

Quite apart from the issue of the fudged data in the recent instrumental record, looking at past actual temperature variations shows that the worst case projections for global warming aren't even close to what has already happened. The self-playing gif below is one graph that keeps telescoping out to show a greater timeline.

http://wattsupwithth...nim_hi-def3.gif

I ordered my copy of "The Hockey Stick Illusion". Should get it on Monday.

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Here is NPR's take on methane. I'm not concerned about it, though. It seems to me that the most important question is whether or not clouds offer positive or negative feedback. If they are a positive feedback we'll see "runaway warming." If negative, we'll have to adjust to some small changes.

Warming of any sort means more water vapor in the atmosphere, which means more clouds. If clouds offer positive feedback, I guess we're doomed. But it seems way more likely to me that clouds are a negative feedback mechanism, offering a bad-ass counterweight to every other greenhouse gas - meaning that global warming is at worst an inconvenience.

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  • 2 years later...

It seems to me that the most important question is whether or not clouds offer positive or negative feedback. If they are a positive feedback we'll see "runaway warming." If negative, we'll have to adjust to some small changes.

Warming of any sort means more water vapor in the atmosphere, which means more clouds. If clouds offer positive feedback, I guess we're doomed. But it seems way more likely to me that clouds are a negative feedback mechanism, offering a bad-ass counterweight to every other greenhouse gas - meaning that global warming is at worst an inconvenience.

 

The first statement is a bit overstated – there will not be "runaway warming" if cloud feedback is positive. In general the climate settles *eventually* into a new radiative equilibrium state, but feedbacks cause it to "drift" (unless for some reason there is literally no end to the feedback, which is not usually the case. E.g. here, once the world is mostly covered with clouds that particular feedback would end.) 

 

Nor is negative feedback a guarantee global warming is no big deal, it depends on the magnitude. There are already identified negative feebacks. The main argument against net negative feedback is logical – past climate response shows a very clear story around greenhouse and albedo feedbacks accelerating the shifts into and out of "ice age" (glacial) equilibrium states, as the ultimate result of very subtle initial nudges from orbital changes in insolation ("orbital forcing"). A strong negative cloud feedback story should have operated then as well as now, preventing those shifts. Also, the strong positive feedbacks (water vapor – warmer air holds more water, which enhances greenhouse) and ice cover albedo (warming reduces ice extent) are relatively well validated i.e. directly observed in the past four decades etc.

 

Some types of clouds are net negative and some are net positive feedback. Because of this essentially, the trending view is that the overall forcing is smaller rather than larger. The most recent prominent paper on the subject was Sherwood 2014, which looks at the effect of atmospheric mixing (high mixing prevents heavy low level cloud formation, with the paper arguing the real atmosphere looks more like high mixing, i.e. arguing for net positive feedback.)

 

 
Readable article from lead author Sherwood.
 

Note there is enormous asymmetry in risk between the higher and lower assessments of total climate sensitivity; a rational approach to risk management needs to take this into account.

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