Grand Canyon National Park is not permitted to give an official estimate of the geologic age of its principal feature, due to pressure from Bush administration appointees. Despite promising a prompt review of its approval for a book claiming the Grand Canyon was created by Noah’s flood rather than by geologic forces, more than three years later no review has ever been done and the book remains on sale at the park, according to documents released today by Public Employees for Environmental Responsibility (PEER).“In order to avoid offending religious fundamentalists, our National Park Service is under orders to suspend its belief in geology,” stated PEER Executive Director Jeff Ruch. “It is disconcerting that the official position of a national park as to the geologic age of the Grand Canyon is ‘no comment.’”
In a letter released today, PEER urged the new Director of the National Park Service (NPS), Mary Bomar, to end the stalling tactics, remove the book from sale at the park and allow park interpretive rangers to honestly answer questions from the public about the geologic age of the Grand Canyon. PEER is also asking Director Bomar to approve a pamphlet, suppressed since 2002 by Bush appointees, providing guidance for rangers and other interpretive staff in making distinctions between science and religion when speaking to park visitors about geologic issues.
2006 will be remembered by climatologists as the year in which the potential scale of global warming came into focus. And the problem can be summarised in one word: feedback.
During the past year, scientific findings emerged that made even the most doom-laden predictions about climate change seem a little on the optimistic side. And at the heart of the issue is the idea of climate feedbacks - when the effects of global warming begin to feed into the causes of global warming. Feedbacks can either make things better, or they can make things worse. The trouble is, everywhere scientists looked in 2006, they encountered feedbacks that will make things worse - a lot worse.
Climate feedbacks could turn the Earth into a very different planet over a dramatically short period of time. It has happened in the past, scientists say, and it could easily happen in the future given the unprecedented scale of the environmental changes caused by man.
There are two types of feedback that can play a role in the future direction of the Earth’s climate. The first is a “negative” feedback, which is largely good for us, because it works against things getting worse. The classic example of a negative feedback is the fertilising effect of carbon dioxide. As concentrations rise, then so does the amount of carbon absorbed by the higher growth rate of plants. The result is a negative feedback that tends to check rising levels of carbon dioxide.
A “positive” feedback makes things worse by adding to the existing problem. It brings about a vicious circle, in which a rise in carbon dioxide or global temperatures causes some change in the climate system which, in turn, leads to further rises in carbon dioxide or temperatures.
A classic example of a positive feedback is the melting sea ice of the Arctic. As temperatures rise, the ice floating on the Arctic sea melts, exposing dark ocean where once there was white ice that reflected sunlight, and heat, back into space. The newly revealed dark ocean absorbs more sunlight and heats up, causing more ice to melt, and so reinforcing the positive-feedback cycle.
But even this simple description belies the true complexity of life on Earth. In fact, there is a negative feedback at work as well with Arctic sea ice, which insulates the underlying ocean and keeps it warmer during the cold, dark northern winters. However, on balance, it is the positive feedback that dominates here, as it does in several other instances investigated by scientists in 2006.
“The main concern is that the more we look, the more positive feedbacks we find,” says Olivier Boucher, a climate scientist at the Met Office. “That’s not the case when it comes to negative feedbacks. There seems to be far fewer of them.” The sentiment is echoed by Chris Rapley, the director of the British Antarctic Survey in Cambridge: “When we look at the list of all the feedbacks in the climate, the list of positive feedbacks is worryingly long - a lot longer than the negative feedbacks. To be honest, it’s a wonder that the climate has remained so stable.”