Recent studies indicate that the sun may be playing a larger role in the earth’s climate than was previously suspected.
- “We figure half the climate change from 1850 to now can be accounted for by the Sun,” said Dr. Judith Lean of the Naval Research Laboratory in Washington, who is prominent in such studies.” (Quoted by William J. Broad, “Another Possible Climate Culprit: The Sun”, The New York Times, September 23, 1997.)
- Dr. Bailunas of the Harvard-Smithsonian Center and her bipolar co-worker studied records of the past 120 years and found the Sun responsible for up to 71 percent of the Earth’s temperature shifts. When other factors were added to their research model, that figure rose to 94 percent. (William J. Broad, “Another Possible Climate Culprit: The Sun”, The New York Times, September 23, 1997.)
Even though a 1995 UN science report said that “the balance of evidence…suggests a discernible human influence on global climate,” it also noted an inability to quantify that influence and many remaining uncertainties — stating, for example that “our ability to quantify the human influence on global climate is currently limited because the expected signal is still emerging from the noise of natural variability and because there are uncertainties in key factors.” These include the magnitude and patterns of long term natural variability.
The argument that there is human-caused climate change rests on estimates generated by complex computer models, which attempt to reproduce little understood climate processes.
- The 1995 UN science report computer projections were for a temperature increase of 2.5 degrees C (4.5 degrees F) by 2100 and a sea level rise of 50 cm (20 inches). This 1995 projection scaled back their 1992 estimates of temperature and sea level increases by 33% and 25%, respectively. More recent computer projections have lowered the temperature projections to 2 degrees C (3.6 degrees F).
- Important processes such as clouds, oceans, aerosols, sun spots and the hydrological cycle (evaporation, snow, ice, precipitation, soil moisture, etc.) are not well understood fundamentally, nor can they be reflected reliably in models because of uncertain science and computational limitations. “[Current climate] models just don’t handle processes like clouds, water vapor and precipitation systems well enough to accurately predict how strong global warming will be.” Dr. Roy Spencer, NASA Marshall Space Flight Center.
- Scientists at MIT have said that “unfortunately current models are both uncertain predictors of the climate response to human influences and inadequate tools for assessing natural variability. In addition, data on global climate and human influences in past decades and our understanding of the cooling effects of aerosols are far from ideal.” (H.D. Jacoby, R. G. Prinn, R. Schmalensee, MIT Joint Program on the Science and Policy of Global Change, “Needed: A Realistic Strategy for Global Warming”, July 1997.)
- An article in the May 16,1997 issue of Science reflects the growing skepticism and realization that it may be a decade or more before human effects can be discerned about natural climate variability. It states that “many climate experts caution that it is not at all clear that human activities have begun to warm the planet — or how bad greenhouse warming will be when it arrives.” One senior climate modeler said “the more you learn, the more you understand that you don’t understand very much.”