Small island nations are calling for an agreement at the U.N. climate summit that will see a mean global temperature increase of just 1.5°C.
Credit: John Pickrell
Will it take some a mega-catastrophe that kills hundreds of thousands, or even millions, before governments take climate change seriously?
The nations of the world can't even come to a binding agreement on how to take steps that would keep global warming from exceeding an average of 2°C, a target preferred by developed countries. But there's plenty of evidence that even this will not be enough to avert disaster.
Two degrees doesn't sound like an awful lot, but it comes into perspective when you consider that global mean temperatures during some parts of the last Ice Age were just 5°C cooler than today. That difference was enough to smother most of North America, Europe and Asia in sheets of ice so thick that they deformed the planet's crust.
The world has already seen an increase of nearly 0.8°C since pre-industrial times, and the impacts are evident from the farmlands of Australia, to the frigid wastes of the Arctic and from the peaks of the Himalayas to the ocean depths.
According to environmental group the World Wildlife Fund (WWF), a 2 to 3°C rise in temperature we will see water shortages for up to three billion people, caused by droughts and melting glaciers.
The world will also see flooding affecting 180 million people in low-lying and coastal regions, and the complete loss of many islands; famines affecting 400 million people; a loss of biodiversity numbering 35% of terrestrial species; and the loss of the majority of coral reefs by 2050.
These reefs protect the coastlines of low-lying nations such as the Seychelles and Maldives, large parts of which are less than two metres above sea level. With no reefs for protection, wave action may sweep them away; even before sea level rises - caused by thermal expansion of seawater, along with melting glaciers and ice caps - plunge them below the water line.
In November 2009, a report from the Environmental Justice Foundation suggested that by 2050, the world could also find itself having to cope with 150 million climate refugees - a possibility grimly illustrated by sculptures of refugees, knee-deep in channels of water, outside Copenhagen's Bella Centre, where the U.N.'s Climate Change summit is being held.
The threat we face from climate change is unparalleled in the history of human civilisation, and that is why continuing questions over the science of global warming are morally reprehensible.
Several weeks ago, hackers broke into computers at the Climate Research Unit (CRU) at Britain's University of East Anglia and stole 13 years' worth of emails. A selection of them - which show CRU scientists in a bad light - were posted on anti-climate change websites, raising questions about the conduct of researchers who play a role in collecting climate data for the top U.N. body, the Intergovernmental Panel on Climate Change (IPCC).
This was leapt upon by climate critics - along with and the delegates from oil-rich Saudi Arabia - who argued that it invalidated much of the science behind global warming.
Some commentators have suggested that the hacking was part of a well-financed and well-coordinated smear campaign aimed at derailling a Copenhagen agreement - and there are even hints that the Russian secret service was behind it.
