What Issues Separate the Consensus and Skeptic Scientists?
There are four elements separating consensus and skeptic scientists. Not all elements are disputed by everyone. The elements are: (1) the amount of temperaturechange since 1850; (2) whether the change is in the range of natural variability or is attributable to humans; (3) the amount of warming that greenhouse gases (CO2 and equivalents) will warm the Earth in the future; and whether for the most likely scenarios, there are more losers than winners and if the change is just different. Underlying these elements are several issues:
Reliance on Computer Models. The sophistication of computer models has advanced steadily over the past few years, to the point that many scientists believe the models are able to forecast future changes in climate. Other scientists believe that the outputs, while interesting, do not match the reality of what happened in prior periods of the Earth's history when the temperature was higher and the CO2 levels 2 to 20 times higher than today. Most also believe the Earth system is far too complex, with too many unknown drivers and feedbacks, to enable use of models. One example is the El Niño phenomenon, which is not reliably modeled after decades of study. Another is that there are indications that the models are wrong in the drought predictions in the tropics and subtropics. Paleo data shows that deserts were wetter during prior warm periods and a May, 2007 paper in Nature points out that there is a ~6.5% rise in precip per deg C, while the models only use 1-3%, an error of 3X! in results. This explains better the satellite obs of a greener, wetter Earth (NASA). The models cannot be initialized to current conditions and are unable to correctly incorporate the major decadal scale vents such as the NAO and the PDO, that control our climate in the northern hemisphere (Dr. Kevin Trenberth, IPCC Author).
Computer models are too coarse. Everyone knows the models should have finer resolution, but there are computational constraints and staffing constraints to develop models at the regional or even local scale. The skeptics argue that this is part of the overstating of impacts. for example. a mountainous area the size of a large country may have an average height that is barely above sea level. The rain-producing mountains that intercept sea-breezes do not exist in the model and the result of the simulation understates future rainfall for the region. There is also a problem in the use of average temperatures in that they do not capture the difference in density and humidity.
The models do not seem correct. The warming of the ocean, the warming of the land, the rise of sea level are all coming in below projections, while much more rain is falling, as the time series grows and even as the models are "adjusted" to reflect the observations, casting their basic premises into doubt. On 22 June, 2007 (Dr. Nils-Axel Mörner) we learned that data were manipulated to create an acceleration in sea level rise. Warming should be detected through an acceleration in the rate of rise and that rise should slow the Earth's rotation. Neither has occurred.
Attribution of the warming trend to human activities. The consensus scientists believe their models can replicate reasonably enough the contribution of human-caused greenhouse gases and thus they can be used to estimate future warming. The other scientists believe this is not the case. The reasons vary among the scientists, but the most common ones are: CO2, the target gas, pales in its abilities to impact temperature compared to water vapor and solar variability (not just radiation but also magnetic flux (which controls cosmic radiation and cloudiness) and orbital mechanics). Some scientists believe that CO2 is actually a cooling gas and we need to look elsewhere. Additional factors that some skeptics believe are not adequately considered are the natural contributions of CO2 and other gases that dwarf the human component and the impact of cosmic radiation on the formation of clouds. Also, it is not clear to some scientists whether CO2 increases lead to warming or whether warming leads to CO2 increases. To many skeptics, the over valuation of CO2 as a causative agent, particularly in light of it having a logarithmic function that decreases impact with the amount of CO2, is an indication of a policy agenda meant to deter the use of fossil fuels, not understand climate change.
This warming may be natural variability. While most scientists believe that the observed warming is real, some believe that it is so slight that we can't be sure that instrument calibration problems and urban heat island impacts have been dealt with adequately. If not, it has not been for lack of effort. The problems are immense. For example, in 1999, Los Angeles moved its data station 4 miles to an area outside the city that is lower in elevation and nearer the coast, with cooler, drier, and less extreme conditions. Even when a location has not moved, the rising temperatures may reflect the growth of a community, or land use changes, around it. Calibration is daunting for calibrating the instruments themselves. An example is relating sea surface temperatures that were derived from a thermometer placed in a bucket of water pulled from the ocean in 1860, with a continuous stream of data taken from a ship's water inlet much deeper in the water in the 1960s, data from drifting and moored buoys transmitted by satellite in the 1980s, and with satellite data from the very top layer of the surface since the 1970s. Perhaps only time will really tell. Many skeptic scientists believe that the trend line turned in 1998 for the present cycle, while many consensus scientists are quick to point out that we are still having temperatures above average, and in turn, the skeptics claim that there is no real way to compute a global average. Lastly, the best data are from the USA. According to NOAA, 2006 was the warmest year in U.S. records, almost the same as 1936. The skeptics say that if only rural sites are used, the temperature actually falls, indicating that in the US, and probably the world, what has been measured is the growth of cities and the heat they absorb and generate; there is no warming.
This warming is largely recovery from the Little Ice Age. The natural rate of increase of about 1 deg F (0.5 C) since the LIA (~1500-1900) has not been removed from the IPCC estimations of temperature rise. The CO2 contribution is negligible or non-existent because there is no credible way to compensate for the sharp cooling from 1940 to the 1970s in the face of the rapid growth of CO2, nor the similar (to present) rise from 1920 to 1940 in the absence of rapid CO2 growth. See for example, Is the Earth still recovering from the “Little Ice Age”?: A possible cause of global warming by Syun-Ichi Akasofu (7 May 2007) . Another difficulty with accepting the temperature rise at face value is the evidence that the start of the use of thermometers in about 1850 comes at the same time as the emergence from the coldest period in 8,000 years.
The rate of warming is dangerous. Not so, say the skeptics, pointing out that the rate of warming from 1980 to 1998 has been seen before, and for many parts of the Earth such temperature changes are recurrent, such as when the Atlantic and Pacific and ENSO (el Niño) oscillations change state, causing immediate massive changes in ocean environments of fish, corals, and marine mammals.
Sensationalist press not counteracted. The fact that Antarctica is warming in the area nearest Chile gets heralded, but the IPCC science documents show that, as a whole, Antarctica is stable. Flooding of coasts and cities, attributed to warming, is not countered by the IPCC, even though its science document shows no discernible acceleration in the rate of rise, a solid indicator of warming and necessary for prior sea level projections.
Warming Impacts. Many scientists in the consensus group believe that the IPCC estimates of temperature rise are accurate and the impact from these changes will be bad for the Earth, its ecosystems, and its people. Other scientists, even if accepting the IPCC forecasts, believe that the Earth was warmer before and with higher CO2 levels and that these were among the most ecologically productive periods in terms of speciation and biomass. This contrasts sharply with periods of glaciation, the ice ages, that come and go whether humans have any influence or not. A case in point is my testimony which shows the paleo record tells us that corals were very expansive when the Earth was warmer and CO2 much higher, whereas 3 other scientists testified that corals were in grave danger, even now, due to the high temperatures and acidification of the ocean caused by CO2.
An Average Wrong Answer. The IPCC reliance on emission scenarios, and then presenting all the outputs of temperature rise and impacts as if they had somewhat equal probability, leads to an average wrong answer and exaggerated impact assessments.
Influence of the Sun. Scientists affiliated with the Consensus believe solar influences are not important to the recent warming and that are actually in the wrong direction (See recent paper by Lockwood and Frohlich). Other scientists believe that the analysis is flawed and that the actual mechanisms through which the Sun affects Earth climate were not used in the analysis (for example, Whitehouse). Many solar scientists believe that most of the Earth's temperature variation is explained by the sun's activity and our proximity to it (Scafetta and West).
