By Frank J. Dinan
There is a broad scientific consensus that human generated carbon dioxide plays a large role in global climate change, but a vocal minority rejects this view. From either perspective, our attention has been almost exclusively focused on carbon dioxide as a primary cause of global climate change. But today, another gas potentially causing global climate change must be considered: methane (natural) gas.
Methane has been in the news a great deal lately since it has become available in immense quantities due to the development of hydraulic fracturing. This controversial technology allows us to release vast quantities of methane gas stored within the earth's crust. It has led to methane being touted as the abundantly available clean fuel for the future. Some argue methane's abundant availability gives the United States the potential to become a net energy exporter.
As methane becomes increasingly abundant, its potential for causing environmental problems if it is handled improperly increases. The Environmental Protection Agency has determined that methane has a Global Warming Potential (GWP) 23 times greater than that of carbon dioxide. This means that methane is that many times as effective as carbon dioxide at blanketing the earth to prevent the escape of its heat.
But there is yet another enormous potential source of methane gas entering our atmosphere, one that is far more difficult to control: methane hydrates. These are ice-like crystals found in permafrost. These hydrates are stable at low temperatures but melt to release methane gas when they are allowed to warm. The permafrost regions of the Arctic stretch all around the globe and contain incalculably great amounts of methane hydrates. Satellite photos that document the rapid loss of sea ice leave no doubt that these Arctic regions are warming rapidly.
The GWP of methane gas combined with the rapid warming of the Arctic give rise to a potentially disastrous positive feedback loop. As the Arctic's permafrost regions warm, methane gas is released. Methane's high GWP assures that the Earth will warm even more rapidly as the gas enters our atmosphere. This increased warming will result in methane being released even more rapidly, thereby establishing a snowballing feedback cycle leading to increasingly rapid climate change. Research documents that 48 million tons of methane are entering our atmosphere from eastern Siberian permafrost alone each year. That amount is sure to grow.
Global warming, significant as it seems today, is in its early stages. The role of carbon dioxide as its cause is being studied and argued aggressively. In contrast the rapidly growing role that methane is sure to play in climate change receives little attention. It surely must be considered if we are to control our climate's future.
Frank J. Dinan is an emeritus professor of chemistry at Canisius College.