A Climate Science Headline You Won't See: Climate Feedbacks Less Than Supposed

[LowDown]

Roy Spencer and a colleague caused a lot of brouhaha when they published a paper showing that climate feedbacks from water vapor were much less strongly positive than had been assumed in climate models. They did this using data from the Terra satellite by assuming that effects of sea surface heating would show up as lagged changes in clouds and surface temperatures. In short, the sun heats up the ocean in the tropics which evaporates and increases humidity. This results in cloud formation that cools down the ocean. So the overall effect is for less heating than one would suppose from analysis of cloud free days as had been done by previous investigators who didn't account for the lag.

The publication of this paper raised such a stink that the journal editor was forced to resign. This ugly scene may have angered or embarrassed editors who believe in free and open inquirely or are concerned about their public image. Articles calling the models into question are suddenly appearing.

Now, a paper published in the peer reviewed journal Theoretic and Applied Climatology appears to confirm Spencer et al's results.

What this means is that the feedback from water vapor is much lower than has been assumed by modelers, which means that their predictions of increases of global temperatures of 4 to 6 degrees with doubling of CO2 in the atmosphere are too high. The correct figure is more like 1.5 to 2 degrees.

The wheels of science turn slowly but finely.

HT: The Hockey Schtick

 

[joG]

Roy Spencer and a colleague caused a lot of brouhaha when they published a paper showing that climate feedbacks from water vapor were much less strongly positive than had been assumed in climate models. They did this using data from the Terra satellite by assuming that effects of sea surface heating would show up as lagged changes in clouds and surface temperatures. In short, the sun heats up the ocean in the tropics which evaporates and increases humidity. This results in cloud formation that cools down the ocean. So the overall effect is for less heating than one would suppose from analysis of cloud free days as had been done by previous investigators who didn't account for the lag.

The publication of this paper raised such a stink that the journal editor was forced to resign. This ugly scene may have angered or embarrassed editors who believe in free and open inquirely or are concerned about their public image. Articles calling the models into question are suddenly appearing.

Now, a paper published in the peer reviewed journal Theoretic and Applied Climatology appears to confirm Spencer et al's results.

What this means is that the feedback from water vapor is much lower than has been assumed by modelers, which means that their predictions of increases of global temperatures of 4 to 6 degrees with doubling of CO2 in the atmosphere are too high. The correct figure is more like 1.5 to 2 degrees.

The wheels of science turn slowly but finely.

HT: The Hockey Schtick

That is just about what I have been seeing. Wouldn't it be a pity, if we had hurried the alternative energy revolution and installed all that unfinished technology for nothing.

 

[longview]

That is just about what I have been seeing. Wouldn't it be a pity, if we had hurried the alternative energy revolution and installed all that unfinished technology for nothing.

Only it would not be for nothing, it costs us plenty, monies that could have been
spent on the outside of the box thinking, that will be necessary for long term energy
solvency.

 

[joG]

Only it would not be for nothing, it costs us plenty, monies that could have been
spent on the outside of the box thinking, that will be necessary for long term energy
solvency.

No, it was not for free. And we have a lot of old technology to show for it.

 

[LowDown]

Roy Spencer and a colleague caused a lot of brouhaha when they published a paper showing that climate feedbacks from water vapor were much less strongly positive than had been assumed in climate models. They did this using data from the Terra satellite by assuming that effects of sea surface heating would show up as lagged changes in clouds and surface temperatures. In short, the sun heats up the ocean in the tropics which evaporates and increases humidity. This results in cloud formation that cools down the ocean. So the overall effect is for less heating than one would suppose from analysis of cloud free days as had been done by previous investigators who didn't account for the lag.

The publication of this paper raised such a stink that the journal editor was forced to resign. This ugly scene may have angered or embarrassed editors who believe in free and open inquirely or are concerned about their public image. Articles calling the models into question are suddenly appearing.

Now, a paper published in the peer reviewed journal Theoretic and Applied Climatology appears to confirm Spencer et al's results.

What this means is that the feedback from water vapor is much lower than has been assumed by modelers, which means that their predictions of increases of global temperatures of 4 to 6 degrees with doubling of CO2 in the atmosphere are too high. The correct figure is more like 1.5 to 2 degrees.

The wheels of science turn slowly but finely.

HT: The Hockey Schtick

I should make a correction here. What Spencer and Braswell say in this paper is that it's not possible to determine the feedback from the satellite data and that variation of clouds obscures the radiative feedback signal. You kind of have to read between the lines to come up with the mechanism I described in the OP and the conclusion that the feedback is lower than previously supposed. On the other hand, Spencer has explicitly said as much in other peer reviewed papers.

On a clear day with no clouds the satellite sees the positive feedback from water vapor in terms of reducing heat flux into space with a given surface temperature. But this is an artifical number because seldom is there a cloudless day in the tropics. The problem concerns what the clouds are doing in terms of reducing humidity and blocking radiation from the sun because all of that has to be brought together to get the true feedback. Lindzen and Spencer have both written elsewhere that cloud formation reduces the feedback in a manner that is not adequately accounted for in climate models.