A boy holds a globe, that depicts the effects of global warming, while he returns from a rally organized to mark World Environment Day in Kathmandu June 5, 2012.
Credits: REUTERS/Navesh Chitrakar
A draft of the UN's next five-year assessment report has been leaked and appears to show what the skeptics have been saying for years: Carbon dioxide has less effect on global temperatures than thought, the sun is a bigger "driver" of climate change, and global temperatures have not risen appreciably in the past 16 years.
We skeptics need to take a breath. I have no doubt the draft of AR5 (Fifth Assessment Report) says exactly what the skeptics claim, namely that the UN and its Intergovernmental Panel on Climate Change (IPCC) has overestimated the effect CO2 has on global temperatures, underestimated the effects of the giant ball of burning gas in the sky and, as a consequence, incorrectly predicted how much Earth will warm in the coming century.
It's a fact, though, that in the climate change debate, the truth doesn't matter.
In each of the previous four assessment reports, there have been effectively two reports - one for scientists and another for political leaders and the media. The one for leaders and reporters, known as the Summary for Policymakers, has always been far more definitive and alarmist. These sections have insisted the science was settled, even as the main body for scientists has contained a lot more doubt.
Even the scientific sides have made dubious claims, though. In AR2, prominent skeptics who had initially been invited to contribute found their work dropped without notice at the last minute. A "hockey-stick" temperature graph - showing centuries of stable temperatures followed by a sharp upward spike during the industrial age - featured prominently in several places in AR3, even though the data it was based on was highly dubious.
And the scientific sections of AR4 were rife with errors, from unverified claims about disappearing Himalayan glaciers to a sensationalized report on rainforest devastation done by an eco-activist and a freelance journalist.
The point is, UN climate change agencies have always been far more about the politics of global warming and far less about the science. The science typically only figures when it suits the political ends of alarmist scientists and UN bureaucrats.
So skeptics should not hope the latest revelations will stop the constant drumbeat of environmental alarmism emanating from national capitals, enviro lobbies, ivory towers and the IPCC. If this is mostly a political exercise, scientific data will be powerless to derail it.
The leaked copy of AR5 posted on skeptic websites such as wattsupwiththat.com, does indeed show an increasing number of scientists think the effects of CO2 on climate have been overestimated.
The theory to date has been that an increase of CO2 from human sources would raise global temps by around 1C by 2100. This heat would lead to increased evaporation of the oceans that would, in turn, trigger a "feedback" in which water vapour in the atmosphere would increase, trapping still more heat near the surface.
This worked in the elaborate computer models alarmist scientists created, but so far there has been little evidence of the vapour feedback in the real world.
Conversely, the draft AR5 concedes alarmists have been too quick to dismiss the sun's impact on climate change. Also, there is no evidence that the frequency and severity of storms, droughts and floods is increasing globally.
While this should change the debate, it won't. These details will either be expunged from the final report or ignored in the highly ideological summary. The alarmist cause will go on.