The public discussion on climate change has become so polarized that some scientists don’t even acknowledge there is a debate. Climate scientist at NASA’s Goddard Institute for Space Studies, Gavin Schmidt, is one of those people. “There aren’t ‘two sides’ to the science, nor to the policy response,” Schmidt said. “This implies that the whole thing is just a matter of an opinion – it is not.” Another group of scientists would disagree with Schmidt. In June, the Sixth International Conference on Climate Change took place in Washington D.C. It was organized by The Heartland Institute, headquartered in Chicago, and its primary objective is to “dispute the claim that global warming is a crisis.” In 2008, the organization published a report titled “Nature, Not Human Activity, Rules the Climate.” Its president, Joseph Bast, talking to the journal Nature recently, discussed public opinion on climate change and the ongoing debate. “We’ve won the public opinion debate, and we’ve won the political debate as well,” Bast said, “but the scientific debate is a source of enormous frustration.”
The climate change debate, as it discussed in the mainstream media, appears to be divided into two major sides. One side argues that the current global warming is caused by human factors while the other side insists it is occurring because of natural forces. In the latter argument, two natural causes that dominate the conversation are solar changes and changes to the Earth’s orbit.
Scientists and astronomers have studied the impact of the Sun on the Earth’s climate as far back as the early 1800s. Historians have traced the earliest such studies to the research of Sir William Herschel, who tried to link the frequency of sunspots to the price of wheat. His belief was that the number of sunspots would be indicative of the amount of the Sun’s energy that is received by the Earth. That energy would affect the amount of wheat produced, which would affect the price.
Herschel’s study didn’t make a big impact at the time because he did not have access to historical temperature records to make any useful comparisons. However, there has been a significant amount of research conducted since then to show that variations in the Sun’s energy output have an impact on changes in Earth’s climate. A research study published earlier this year in the Journal of Atmospheric and Solar-Terrestrial Physics provides more evidence of this link between the Sun and the Earth. Through their analysis of historic temperature deviations, geomagnetic activity and the frequency of sunspots, the authors concluded that “the Sun has a significant role to play in the long-term and short-term climate change.”
“With more and more data available, it may provoke some thought to further explore the solar influence on Earth’s climate with geomagnetic activity acting as a possible link,” said lead author Mufti Sabi ud din, scientist of the Astrophysical Sciences Division at the Bhabha Atomic Research Center in India’s Department of Atomic Energy. “It may evoke some response so as to bring to the fore the substantial role of the natural forcing at work on the observed climate variability.”
Mufti, however, did note that the evidence of the Sun and other natural forces being the primary cause for climate change is still inadequate. “We do not rule out the natural forgings at work,” he said, “but there isn’t enough quantitative evidence to say that natural forgings are the dominant cause of current climate change.” Pointing out the geopolitical sensitivity of the topic itself, Mufti was careful not to rule out anthropogenic effects. “We have made it amply clear that the anthropogenic origins cannot also be ruled out,” Mufti said. According to Schmidt, while the Sun does have some impact, it is definitively not the reason for current patterns of climate change. “There is an effect,” Schmidt said, “but it is hard to detect in surface records and is certainly not responsible for recent trends.”