As even proponents of global warming concerns admit, the facts about warming and its causes should drive public policy about it. But in declaring the argument “closed,” they are finding it increasingly necessary to ignore the facts. It is important that the public not allow them to shoulder the evidence aside.
There is more evidence every day. Scientists report in the July 6 issue of Science magazine that rich boreal forests covered much of Greenland just a few hundred thousand years ago, refuting claims by global warming alarmists that current temperatures are abnormally warm.
The scientists drilled more than a mile deep into the Greenland ice cap and discovered that before advancing ice sheets claimed Greenland a few hundred thousand years ago, plant and animal life thrived in temperatures that were approximately 15 degrees Celsius warmer than today. The implications are enormous for determining just what is and is not “normal” planetary warmth.
Greenland’s naturally oscillating climate is a central focus of global warming science. Scientists tell us that under human-induced global warming, polar regions will warm up more quickly than the rest of the planet. If we see significant warming of Greenland and Antarctica, this will be asserted as a sign that the rest of the planet may soon experience much of the same.
The problem for global warming alarmists is that the poles currently show no sign of human-induced global warming. Antarctica is in a prolonged cold spell and is gaining rather than losing ice mass. While a small portion of West Antarctica is warming and losing ice mass, the vast majority of the continent is getting colder and gaining ice.
In much of the Arctic, temperatures are somewhat warmer than the twentieth century average. However, Arctic temperatures have been relatively stable since a shift in Pacific Ocean currents–completely unrelated to global warming and certainly natural–elevated regional temperatures in the late 1970s.
Greenland, which is buffered from Pacific Ocean currents by Northern Canada, is definitely not warming. In the 1980s and 1990s, Greenland experienced its two coldest decades since the 1910s, and recent temperature readings indicate the cold spell is continuing.
All these facts reassure scientists that humans are having no more than a minor current impact on global temperatures, but they pose a very difficult question: When polar temperatures do inevitably warm, how do we distinguish between the Earth’s natural temperature fluctuations and human-induced warmth?
Global warming alarmists have long asserted that any polar warming would be a sure sign of human influence because temperatures are already at unprecedented levels. The discovery of a boreal forest so recently covering much of Greenland completely refutes that assertion. It proves that temperatures have very recently been much, much warmer than today, and were a result of natural factors, not human activities.
The discovery also makes it clear that more recent periods of planetary warmth were normal. Scientists have discovered that in four distinct interglacial periods since boreal forests covered Greenland, temperatures were at least 3 degrees Celsius higher than they are today.
Thus, even if Greenland were to start warming, the case for humans being the cause would remain tenuous at best. Dramatic planetary warming would have to occur for quite some time before we would even approach the warmth that has occurred frequently in our planet’s recent past.
The more we learn about the recent temperature history of our planet, the more tenuous become assertions by global warming alarmists that humans are causing an alarming and unprecedented warming of our planet.
James M. Taylor ([email protected]) is senior fellow for environment policy at The Heartland Institute.