Global Warming is Man-Made

AGW exists, it but doesn't dominate climate Greenhouse gases cause warming, and I never claimed otherwise. Pro cited a skeptical climate scientist acknowledgment that AGW plays some role in climate. Our resolution is “Global warming is man made.” That might mean that global warming is entirely man made, in which case Pro has conceded it is not, because he has acknowledged that there are also natural causes. I didn't take that meaning. I said repeatedly that Pro must prove that climate is dominated by AGW. I must prove it does not. The proof of AGW would be a AGW math mathematical model of climate that accurately explains and predicts. Weather effects are yearly variations; climate comprises trends over several years. The AGW models fail because the models do not predict or explain climate the large trends in climate. For example, Pro acknowledges that Medieval Warm Period was due to solar activity, but the official IPCC models have no mechanism that explains the MWP. Because AGW models cannot explain the MWP, climate crisis advocates have fought consistently to make the MWP disappear as a global climate phenomena. The Hockey Stick got rid of it by a statistical error, but the data ultimately won. A change in climate acknowledged to be very close to modern warming is unexplained by the models we are supposed to accept as reliable. The pause in global warming is real Pro argued that an 17 year pause in global warming might just be “noise,” and he cited a scientific paper that allegedly shows that. That's bad science. Suppose an engineer designed a building taking into account all the other factors he knew to affect design, and the building subsequently collapsed. Consider: “The design models were correct. The building collapsed due to unknown factors categorized as noise. There is no need for further explanation.” Nonsense. Fundamental failures are not noise. An eighteen year failure of climate prediction shows that the model is defective. Since AGW is in the model, and something else canceled it, the unknown factor dominated climate over the period. I quoted both HADCru and NASA scientists as acknowledging the pause in global warming. The paper by AGW-advocate von Storch established that the current models cannot be tweaked to explain the pause. Pro found some oddball paper that made a model that shows a pause, but models can be made to do anything desired. AGW theory is not validated until after it makes accurate predictions. Making a new, unproved model means we are back to the starting point. Pro said that HADCru land data showed an increase. Year-to-year variations occur with weather, and so there is so uncertainty in the trends due to the accuracy of fitting a line through the weather-induced variations. The HADCru data shows 0.09 +/- 0.11 degree of global warming over the period of the pause, compared to the 0.4 to 1 degree predicted by the AGW models. None of the six global temperature data sets showed a statistically significant increase. [http://wattsupwiththat.com...] The land data sets are the least accurate because increasing urbanization drives up the temperatures near many of the weather station locations, due to the so-called “heat island” effect. The satellite data is the most accurate because it samples the earth uniformly, and it shows no increase. HADCru scientists understand the large departure from the models, and acknowledge the pause. Pro said I acknowledged that the Sun could not be causing the pause in global warming. That's not true, but if it were true, it would not help Pro's case. If it's not the sun, then a completely unsuspected factor dominated climate and overwhelmed AGW. However, what I acknowledged was that the length of the previous solar cycle was not a good predictor. I presented the historical graph that showed the level of sunspot activity correlated well with the warmth of the MWP, the cold of the Little Ice Age, and the warming of the 20th century. Pro acknowledged the solar cause of those changes. Sunspots do not correlate to the heat output of the sun, so the effect on climate must be a different physical cause: magnetic field, cosmic rays, ultraviolet spectrum, or something else. It might be some complex combination of the effects. The graphs show that cold climate is associated with low sunspot activity and warm climate with high sunspot activity. The 20th century covered a long period of high sunspot activity, which explains the warming. Recently, sunspot activity has dropped, correlated to the pause. The number of sunspots remains a reliable longer term climate predictor. AGW predicts straight line temperature increase I presented a graph showing actual global temperatures and AGW predicting a strong straight line increase. My graph is accurate, but I should have better explained the AGW line in comparison to the actual climate data. Here is the graph, repeated from the earlier round: Temperature responds to the logarithm of greenhouse gas density, and greenhouse gas density has been increasing exponentially. The log of an exponential is a straight line. As far as I know, all climate scientists agree on this. Therefore, AGW should produce a straight line. Pro said that the models also include some natural effects like volcanoes, so the model predictions need not be a straight line increase. However, the debate resolution is that AGW dominates climate. While natural causes upset the perfect straight line behavior to some degree, they cannot dominate. While there may be some blips, like the blip of cold for a couple years from the eruption of Mt. Pinatubo, there should be no problem recognizing a straight line. The temperature data is not close to any straight line, so AGW is not dominating. We are far below what the models predict for the present year. The slope of the line of temperature increase over time depends both on climate sensitivity and the rate of carbon dioxide increase. The behavior of temperature with CO2 is logarithmic, so Pro's computation of what it should be is way off. Initially a small increase in CO2 produces a large increase in temperature, with later increases in CO2 having less and less effect. Suppose CO2 increased in units from 1 to 16, and that the increase from from 1 to 2 brought one degree of warming. That means that there would be four degrees of warming at 16, CO2 having doubled four times. Linear interpolation, which is what Pro did, between 1 and 16 says that there should be (1/15) of the 4 degrees, 0.27 degree, at 2 units. In fact, there was 1 degree of increase at the 2 unit point, four times as much as linear interpolation erroneously yields. The temperature rise is not line between 1 and 2 or between 2 and 4, or anywhere on the curve. I converted the combined effect of climate sensitivity and CO2 increase into a linear number of degrees increase per century increase. The official estimate by the US Environment Protection Agency, referencing the IPCC, is 2.2 to 6.1 degrees C by 2100. (I converted from the EPA's F) [http://www.epa.gov...] That's 2.6 to 7.1 degrees per century. The range includes both the allowed variation in the estimates of climate sensitivity and the possibility that CO2 output may drop near the end of the century, as substitutes for fossil fuels become more significant. Departure from exponential growth is in the future so I used 3 degrees per century to represent the low end of climate sensitivity estimates that AGW theory allows. It's a coincidence that matches 3 degrees for doubling CO2. The earth should have warmed by 0.4 to 1 degree since 2000, but in fact as measured by the satellites there was no change, and in all data sets show no statistically significant change. The graph shows temperature anomaly, so where the blue line ought to originate depends upon when one believes AGW began to dominate climate. AGW theory was invented to explain the temperature rise from about 1980 to 1996, so that's where I put the AGW prediction line. The Hockey stick claimed that nothing happened to climate for a thousand years before about 1970. If the claim is that AGW dominated the entire 20th century, then the line should start at 1900. If climate sensitivity is 0.7, way below any AGW official estimate, then the line is about 0.5 degree per century. and AGW no longer explains the rise in the 80s and 90s. Wrong consensus derives from common error When science reaches a wrong consensus, scientists point to the data that they used to proclaim that the wrong consensus is well founded. I gave several examples. For AGW, it was the rapid temperature increase in the 80s and 90s that “proved” the theory. Some AGW is in the climate, but the long pause proves it is not the dominant factor. Paleoclimate In the hundred million year history of climate, CO2 shows no relation to temperature. The laws of nature do not change. It's not enough to say that things were different back then. The changes in the orbit of the earth were too small to explain the climate variation. The likely missing link is the solar variation other than heat output that caused the MWP. CO2 released from the ocean will increase heating, and CO2 going back into solution will amplify cooling. Those are natural, not anthropogenic, factors and they do nothing to explain what drives the trend in either direction. (I wrongly identified my reference for the lag in CO2; it's 3-5.) The Debate Pro's rules for the debate say that we have an equal burden to prove that AGW does or not dominate climate. That's fine with me. If AGW was the dominant factor in climate, then we should have observed a straight line increase in temperature since 1980, and we clearly have not. Since Pro has not met his burden of showing that AGW dominates, I've met my burden to show it has not. Thanks to Pro for a fine debate. It will be most fascinating to people interested in logarithms.