Global warming: an ongoing issue

Troy Chamberlain and Troy Chamberlain

It may become difficult this upcoming spring semester to believe that global warming exists while walking to class in bone-rattling cold, through snow so deep it threatens to capsize Ugg boots.

There is much more to this issue however, than perceptible temperature variations in localized regions. It requires an evaluation of mean surface temperatures globally which, according to weather and climate professor Ted Eckmann, have increased by around .8 degrees Celsius over the last 50 years or so. The gravity of the situation, said Environmental Action Group Vice President Laura Winebarger, will weigh on all, whether they believe in it or not.

‘Global warming is going to affect everyone, everywhere. No matter what,’ Winebarger said.

The leading theory for the cause of rising global temperatures is increased atmospheric carbon dioxide levels, resulting from emissions caused by human activity. According to Realclimate.org, carbon dioxide levels have increased from roughly 280 ppm (parts per million) to 380 ppm over the last 150 years or so; graphs created by Eckmann show strong correlations between these increases and the onset of the industrial revolution.

Carbon dioxide and other various greenhouse gases, Eckmann said, occur naturally and are necessary to ensure a climate conducive to life as we know it. These gases act to absorb radiation from the sun and the earth alike, which would otherwise escape into space. Upon absorption, these gases then heat up and emit their own radiation, which in turn, warms the earth and impacts global climate. Eckmann said problems arise when the abundance of these gases becomes too great, as is happening now due to increased emissions. This results in an unnaturally accelerated warming of the planet.

Eckmann said while there are many factors which play a role in climate change both now and in the history of the planet, such as solar output and plate tectonics’ influence on oceanic currents, none have as strong a relevance in current trends as increased carbon dioxide levels.

‘In terms of the last couple hundred years’hellip; [climate change] is almost entirely due to carbon dioxide emissions,’ he said.

Apart from increasing global temperature observations, the diminishing of polar ice caps, also provide a compelling case for the warming argument, Eckmann said. Satellite observations have shown that the ice caps are shrinking. This could result in rising sea levels and decreased reflectivity of the planet, which may then perpetuate the warming trend, allowing the planet to absorb more of the sun’s radiation.

There is existing evidence, however, to contradict the assertion we are losing ice. Scientists George Kukla and Joyce Gavin of the Lamont-Doherty Earth Observatory, a research site of Columbia University in Palisades, N.Y., stated increased snow accumulation may be resulting in a thickening of the polar ice caps at their center. Though paradoxical in nature, global warming could result in glaciation – expanding of polar ice caps – they said. In a study conducted by the two scientists, they proposed the theory that the precession of the earth relative to the sun has affected past climates and is affecting the current one as well. Precession is the seasonal timing of the closest (perihelion) and the farthest (aphelion) approach of the earth to the sun in its annual orbit.

Using data correlations of ‘radiometrically dated paleoclimatic evidence of past orbital variations computed from the laws of celestial mechanics,’ Kukla and Gavin showed changes in past precessions have affected global climate. Current shifts in precession, they say, are ‘qualitatively similar’ to those in past models which coincided with climate change and glaciation.

Precession, they said, can influence climate and glaciation by increasing the insolation of the planet’s oceans. When insolation is higher, the oceans absorb more of the sun’s radiation, which then provides more energy for evaporation, resulting in a poleward shift of ocean water to the ice caps as snow accumulation. Thickening of ice at the poles could provide evidence for this theory.

This complicates the debate over loss of ice, in that ice may not be diminishing, as a net value, but rather redistributing itself to the center of the ice caps, while melting at the peripherals.

Eckmann said though these facts may be true, composite analysis has shown there is indeed a diminishing net quantity of ice on the planet. Even if general abundance remained analogous, he said, thicker but less expansive ice caps could prove problematic for the climate because of their reduced surface area and general reflectivity to the sun’s rays.

Whether increased accumulation will result in an eventual expansion of the ice caps, as proposed by Kukla and Gavin, is yet to be determined. At the conclusion of their study, Kukla and Gavin stated both natural and human induced occurrences are likely to blame for current trends.

When striking correlations were observed in the early 1990’s between solar cycle lengths and northern hemisphere land temperatures, great speculation arose as to whether this negated the significance of increased carbon levels. A 1997 study done by scientists Peter Laut and Jesper Gunderman of the Technical University of Denmark concluded these correlations could not be used to eliminate the role of human activity in climate change, but that the weight of the impact of solar cycle lengths could not be entirely written off either.

Eckmann said though many correlations between climate change, precession and solar cycle lengths exist, they are not significant enough to take away from the emissions theory.

With conflicting theories as to the causes of global warming aside, new controversy raises the question of whether or not the planet is indeed warming at all. According to cbsnews.com, a scandal now popularly being referred to as ‘climate gate,’ has revealed e-mails between top climate scientists in the U.S. and Europe which indicate a possible negligence of data antithetical to claims of rising global temperature. According to reports, these e-mails showed data found in tree ring analysis, which indicated a possible decline in global temperatures from the 1980’s to the present, being integrated with data from other sources to ‘correct’ the findings and instead show a warming trend. This has resulted in criticism, particularly from right wing advocates, as to the authenticity of the scientists’ claims.

Proponents of the warming theory have said these e-mails have been drawn out of context and the allegations of data forging are unfounded. The findings have not affected the United States’ position on the issue as a matter of great concern requiring immediate action.

The salience of the global warming debate in American media and politics is likely to remain high, as stances toward its legitimacy and causes continue to be divided. Despite her confidence in the emissions theory, Winebarger said further research should be done on alternate theories so as to provide the scientific community with a more thorough understanding of this intricate issue. ‘