After 10 years of drought, the tough-minded Australians began to wither under the endless days of clear skies and no rain. As the "Big Dry" of once-in-a-century became a once-in-a-millennium trauma, skepticism about the reality of global warming evaporated in the heat. And many resolute farmers who once withstood anything that Australian weather could deliver now abandoned their farms. The Murray-Darling River system dropped to a mere trickle of itself and could no longer provide sufficient irrigation for the rich array of crops in its adjacent fields. Lakes began to evaporate and rivers acidify. Stringent water rationing became the norm in towns and cities throughout the country (New Scientist, Jan. 4/08).

Enough was enough. If Australians couldn't change the weather, they could at least change their minds. Which is precisely what they did. After 10 years of drought, parched Australians threw out a government that was denying climate change and elected one that was committed to climate action. Within days, the country had signed the Kyoto Protocol – Australia, along with the United States, was one of only two industrialized countries that had not signed the international agreement to combat global warming – and began to search for ways of reducing carbon dioxide emissions. Weather was far more convincing than scientific predictions of climate change.

While drought convinced Australians of global warming, other people are being convinced by other events. Some South Pacific islanders are already abandoning beach-side villages to higher ocean levels. In Bangladesh and India, farmers on lowland deltas are surrendering fields to increasing salinity and rising salt water. Alaskans are trying to cope with collapsing buildings, roads and shorelines as permafrost melts. But most people of the world, particularly if they are wealthy and living in temperate climates, are still sheltered from the serious effects of global warming. Although they are still not taking the threat very seriously, many of their scientists are.

Most scientists are characteristically apolitical – their inherent inclination is to avoid politics, just do science, present their findings and then return to the laboratory for more research. So their new political activism marks a significant shift in attitude and must be taken as a measure of the growing seriousness of climate change.

Probably the first and most noteworthy scientist to "go political" was Dr. James Hansen, the senior climatologist with NASA and the first to identify the phenomenon we now call global warming. He was so concerned about the ramifications for the environment and humanity that he presented his findings to the US Congress in l988. But Dr. Hansen's growing alarm peaked in 2006 when he discovered that zealous young appointees in the Bush administration were editing scientific reports to the US government in order to downplay the seriousness of warnings because, as they said, their job was "to make the president look good".

This politicization of scientific evidence still continues in the US. Over 56% of Environmental Protection Agency scientists say they have experienced at least one type of political interference in the last five years. Francesca Grifo of the Union of Concerned Scientists found "an agency in crisis", with 31% saying they could not speak candidly within the agency and 24% saying they could not do so outside the agency. "Distorting science to accommodate a narrow political agenda," says Grifo, "threatens our environment, our health and our democracy itself" (Guardian Weekly, May 2-8/08).

Similar constraints were, or continue, to be placed on Environment Canada scientists. In January, 2008, they were ordered to refer all media queries to Ottawa where "communication officers" would help them respond with "approved lines" (The Vancouver Sun, Feb. 1/08). "It's insulting," said one senior staff member who, for some reason, didn't want to be identified. Researchers were instructed to no longer discuss or confirm scientific facts without approval from the "highest level". Dr. Andrew Weaver, a Nobel Prize winning climatologist, describes this as "micro-management" and "message control" (Ibid.). "The concept of free speech is non-existent at Environment Canada," he said. "They are manufacturing the message of science" (Ibid.).

This is the political atmosphere that prompted 85 Canadian scientists to publish a protest complaining about the "politicization" and "mistreatment" of science in this country. A similar document came from 124 of Canada's top environmental scientists – virtually the entire academic climate-science community. They wrote and signed a public letter asking Canadians to vote "strategically" in the 2008 federal election, presumably to change the government so they could return to an open dialogue with the public.

Scientists are usually reluctant to become political, doing so only when their scientific freedom is threatened, when their scientific findings are manipulated by political objectives, or when profoundly important scientific evidence is disregarded by governments responsible for taking preventative action. The dampening of free enquiry and communication, coupled with the perceived threat of global warming, have forced scientists into the political arena because, as Dr. Weaver writes, "... people have no idea how serious this issue is."

The hot and parched conditions in Australia are almost certainly the early symptoms of global warming. And this extreme weather is very likely the ominous precursor of other forms of planet-wide climate transformations that will radically alter ecologies, disrupt human settlement and set in motion political turmoil in countries that are less socially stable and disciplined than Australia. If the Australian experience is just the beginning, then our most pressing need is the best of current scientific information unedited by political agendas.