October, 2007 RESEARCH UPDATE: We have submitted a research paper to the Journal of Climate in which we used a simple climate model to demonstrate how natural climate variability in temperature and clouds can be mis-diagnosed as positive feedback (cloud changes with warming that are presumed to amplify the warming, an effect which is programmed into all leading computerized climate models). The misdiagnosis occurs because climate researchers look at cloud variability as a RESULT of temperature variability, when in fact some of the temperature variability is actually caused by the clouds. We also constrained the model with satellite observations in order to estimate the likely magnitude of this positive feedback bias.
August, 2007 RESEARCH UPDATE: Our peer-reviewed paper showing the natural cooling behavior of tropical cirrus clouds in response to warming was published on August 9 in Geophysical Research Letters. (The UAH news release is here.) In that paper we describe satellite evidence for a natural cooling mechanism (‘negative feedback’)that occurs when the tropical atmosphere heats up. This is in contrast to all leading climate models, which have cirrus clouds behaving as a positive feedback, amplifying warming tendencies. [In an unusual turn of events, absolutely no reporters contacted me about these important results. It will be interesting to see whether any climate modelers include this effect in their climate models — a change which would likely greatly reduce the amount of global warming those models predict for the future.]
Here I present a simplified (but hopefully accurate) explanation of the basics of global warming – call it a global warming primer. First, I will address the issue of how warm we are today, and some possible explanations for that warmth. Next, I’ll briefly describe the Earth’s natural greenhouse effect and global warming theory. Finally, I will explain the “thermostatic control” mechanism that I believe stabilizes the climate system against substantial global warming from mankind’s greenhouse gas emissions. Some of what I will present is an extension of Richard Lindzen’s “infrared iris” effect, support for which was published on August 9, 2007 (see August Research Update, above).
The bottom line is this: Precipitation systems ultimately control the magnitude of the Earth’s total greenhouse effect –which is mostly due to water vapor and clouds — and those systems change in ways that offset the small warming tendency from mankind’s greenhouse gas emissions.
Read the entire article ‘Global Warming and Nature’s Thermostat:Precipitation Systems’ by Roy W. Spencer
Malcolm Hill says
This is a very interesting paper.
Now doubt the Duelling Googler and fellow wackos will give it a bollocking because it threatens their world view of things.
Ian Mott says
It highlights the inherent redundancy of much of the CO2 emissions in that the warming that is assumed to take place from the CO2 is already being performed by clouds. And the fact that the GCMs to date have not been adequately factoring in the amount of reflection (cooling) by cirrus and other clouds is clear evidence of an underlying bias to produce pro-warming data.
The variability in the role of clouds is further compounded by whether, and when, they are over land or sea, during daytime or night time, and during summer or winter. And in polar regions, the angle at which insolation strikes a cloud has a very important bearing on the effective thickness of the cloud body and therefore, its reflective capacity.
And it is worth noting that the only way the NOAA/GISS folks could get a suitably lurid tale from their modelling of North Polar conditions was by assuming that cloud cover and composition would remain constant in a warmer world.
In effect, they had chosen to ignore the fundamental science defining dew point, the changes in atmospheric moisture content as temperature increases.
Good work Spencer
Yep – good interesting stuff.
Helen Mahar says
I have also found this interesting. One of the clearest descriptions of Earth’s natural greenhouse effect I have come across.
Then goes on to ask how sensitive our climate system is to changes, questioning a couple of the assumptions used in climate modelling. He points out that there could be a natural cooling process in the preciptation system that kicks in if things get too hot – a negative feedback, and indicates some new evidence from satelites that needs accounting for. He challenges the modellers to incude this natural cooling process into their models, and then see how much global warming these models produce.
Well, with that hypothesis, and that challenge out, someone is going to do it. Good science.
“I believe that precipitation systems act as a thermostat, causing cooling when temperatures get too high, and warming when temperatures get too low. It is amazing to think that the ways in which tiny water droplets and ice particles combine in clouds to form rain and snow could determine the course of global warming, but this might well be the case.
I believe that it is the inadequate handling of precipitation systems — specifically, how they adjust atmospheric moisture contents during changes in temperature — that is the reason for climate model predictions of excessive warming from increasing greenhouse gas emissions. To believe otherwise is to have faith that climate models are sufficiently advanced to contain all of the important processes that control the Earth’s natural greenhouse effect.
I predict that further research will reveal some other cause for the warming we have experienced since the 1970’s — for instance, a change in some feature of the sun’s activity; or, a small change in cloudiness resulting from a small change in the general circulation of the atmosphere (such as the Pacific Decadal Oscillation, ‘PDO’)”
I luv fairy stories about our clouds too
However this cloud stuff is problematic:
Global cloud cover trends inferred from two decades of HIRS observations
W. Paul Menzel National Oceanic and Atmospheric Administration (USA)
Donald P. Wylie Univ. of Wisconsin/Madison (USA)
Darren L. Jackson Cooperative Institute for Research in Environmental Sciences (USA)
John J. Bates National Oceanic and Atmospheric Administration (USA)
Cloud cover information and the frequency of upper tropospheric clouds have been extracted from NOAA/HIRS polar orbiting satellite data from 1979 to 2001. The HIRS/2 sensor was flown on nine satellites from TIROS-N through NOAA 14 during this time forming a consistent 22-year record. CO2 slicing was used to infer cloud amount and height. Trends in cloud cover and high cloud frequency are small in these data. High clouds show small but statistically significant increasing trends in the tropics and northern hemisphere. The HIRS analysis contrasts with that from the ISCCP which shows decreasing trends in both total cloud cover and high clouds during most of this period. The HIRS detection of upper tropospheric thin cirrus creates most of the difference with respect to ISCCP; GLAS observations of high thin clouds are largely in agreement with the HIRS.
Reading through I was looking for another insight to that once freaky Virga and a few other things
In giving clouds a life at the local level there needs to be a lot of observations. Sure weather instruments and models won’t pick them up but with experience we know what’s going on.
Louis Hissink says
It’s the “cloud stuff” that renders GCM’s as silly, silly luke.
I recall seeing some controversial stuff from Spencer & Christy before. This time, Spencer notes that “At least 80 percent of the Earth’s natural greenhouse effect is due to water vapor and clouds, and those are largely under the control of precipitation systems.
“Until we understand how precipitation systems change with warming, I don’t believe we can know how much of our current warming is manmade. Without that knowledge, we can’t predict future climate change with any degree of certainty.”
I thought water vapor and precipitation systems respond as feedbacks to temperature change rather than directly influencing Earth’s energy budget. So how can they call into question whether most of the warming is ultimately forced by CO2 accumulation? And we still have previous research suggesting cloud cover can thin at elevated temperatures, and apparently no explanation for why climate change in prehistory wasn’t stopped by cloud feedback.
Grandpa Louis, strange that GCMs (no apostrophe) do seem to simulate the world’s climate more than you seem to simulate any degree of intelligence.
Paul Biggs says
“apparently no explanation for why climate change in prehistory wasn’t stopped by cloud feedback.”
The role of clouds and water vapor is climate models is the great bogey man to those whose faith and financial backing is rooted in said models. Easily dismissed as “uninfluenced by man” their behavior is just beginning to be understood. Too bad the science is closed on the subject!
I heard Jennifer on RN and it made me look into this a bit more. This may mean models for global warming need to be revised however what does the future hold for climatic patterns other than temperature? Will the trends for changes to the climate (e.g. rainfall events being more intense and fewer of them) continue? If so, this paper is far pfrom revolutionary. A temp rise of a few degrees has big implications but changing rainfall patterns do too.