There was warming in the first 40 years of the 20th century. But this was before the greatest buildup of the greenhouse gases. Then there were 35 years of cooling. You read that right. Between 1940 and the late 1970s, the troposphere temperatures went down, not up. Then in the last twenty-five years, they went up again. Neither of the two computer models used to predict global warming ever suggested any cooling in the twentieth century. Nor does either match the low rate of warming which has sometimes occurred.
The tropospheric temperature record from balloons (radiosondes) starts in the 1950s. We don't have a record of tropospheric temperatures earlier than that. And there are a lot more than two models that have examined past temperature trends. More sophisticated models have discovered that the effect of sulfate aerosols from energy production suppressed warming in the 1940s-1970s. As coal burning plants and other sources were cleaned up, this effect was reduced.
The evidence shows that global warming (and cooling) has been happening at much higher rates than any current projections based on the activity of man, and it was strongest in recent geological history when our European ancestors were still getting nude, painting themselves blue and climbing trees.
During the period 900-1300 AD, it was almost as warm as it is now, BUT the Earth did not warm up into that period, or cool off from it, at anything close to the rate of warming observed in the 20th century, particularly the last 25 years of the 20th century. The most rapid natural rate of change seen in the temperature record over the last 2000 years is about 0.3 degrees C /century. The warming in the 20th century is 0.6 degrees C/century, and the warming in the past 25 years is actually in the range 1.2-1.8 degrees/century. Dr. Baliunas, who is an esteemed researcher, doesn't have an explanation for why the Sun would have caused a more rapid warming this century than in any other century in the last 2000 years.
Natural fluctuations in the atmosphere, in the oceans (including El Nino, which scientists have charted but cannot explain), plus solar variations, explain what has been observed.
What exactly, Congressman Billybob, do you mean that scientists cannot "explain" El Nino? The way that El Nino works is well-known, and predictive capability is improving all the time. Scientists are still searching for a key "initiation" factor for El Nino events, but that's a long way from saying they don't know how to explain it.
You might want to pass on these corrections to your constituents.
I have seen a number of studies that dispute that. In fact, I have seen so many differences among studies of tropospheric temperature to have concluded that we don't yet have an accepted benchmark.
Dr. Baliunas, who is an esteemed researcher, doesn't have an explanation for why the Sun would have caused a more rapid warming this century than in any other century in the last 2000 years.
You are certain that she hasn't accounted for the "urban heat-island effect"?
The correlation between variation solar magnetic cycle lengths and variation of surface temperature over the last 250 years is 0.92. Isn't that good enough for you?
As the article says, "ice cores from the Artic and tree rings" were used to estimate Earth temperatures prior to 1950. You refer to chemical effects which "suppressed warming" for 35 years. It was worse than that for the theory of globol warming. For a third of the 20th century, temperatures went DOWN -- not slower warming or flat, but DOWN.
In 900-1,300 A.D., it was not "almost as warm as it is now," it was WARMER than any other period since the last Ice Age. And none of that warming could be attributed to the activities of men.
Your figures for current warming are wrong.
And, though there are many models for global warming, there are two major ones. NONE of them can account for either the warming or the COOLING that has occurred either in the 20th century, or in the second Millenium.
Concerning El Nino, apparently you agree with me. Scientists are now able to chart it, but none can yet explain it. The "initiation factor," as you say, has not been discovered. It's sort of like understanding light but not understanding a light switch that turns it on and off.
As soon as I can get loadable graphics of the charts that Dr. Baliunas put up during her speech last week, I will post them here. They might help educate you. Earth temperatures are going up and DOWN, and not smoothly in either direction, but sharply in some years. None of the models predict behavior like that.
Theories that cannot fit the facts of the past demonstrate that their predictive value for the future is questionable. It's like all those political science professors who looked at the "critical factors" in prior presidential races and confidently predicted that Al Gore would win, and win big. Of what value are their theories in predicting the next presidential race?
Billybob