Attempts by sceptics to undermine the credibility of fundamental scientific institutions and their research are nothing new, writes Marian Wilkinson.
Amid the thousands of stolen emails from the University of East Anglia's Climate Research Unit, posted on websites late last year, a telling exchange among the scientists has been largely overlooked.
It refers to reports that the US and Saudi Arabian governments had played a key role in picking a new candidate to chair the United Nation's peak scientific body on climate change.
The emails, dating back to April 2002, noted reports of ''intense lobbying'' by the US oil industry, specifically Exxon, to try to persuade officials in President George Bush's White House to block the high-profile British atmospheric chemist, Dr Robert Watson, getting a second term as chairman of the Intergovernmental Panel on Climate Change (IPCC).
Just months before, in September 2001, the IPCC under Watson had delivered its groundbreaking Third Assessment Report, which confirmed that the earth was warming and found there was, ''new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities''.
The finding, supported by the US National Academy of Sciences, provoked a severe backlash from critics of climate change science and figures in the oil and coal industry. Watson, a former science adviser to President Bill Clinton, was viewed by science sceptics and some in industry with deep suspicion.
A memo obtained under freedom of information by a US environment group revealed that Exxon's lobbyist, Randy Randol, wrote to a key Bush official within weeks of the president's inauguration in 2001 asking, ''Can Watson be replaced now at the request of the US?'' By early 2002 the Bush administration was backing a new candidate for the IPCC chair, an Indian engineer, Dr Rajendra Pauchari.
''You may not have seen this latest piece of politicisation from the Bushies,'' the former head of East Anglia's Climate Research Unit, Tom Wigley, wrote in a email to his old colleagues Phil Jones and Mike Hulme in April that year.
That year Jones would come under scrutiny by climate sceptics in the US over data he had used for some critical research to support his finding on rising temperatures in cities.
Jones noted the concerns over the IPPC chairman. But his colleague, Hulme, in a prescient response, argued, ''Why should not an Indian scientist chair IPCC? One could argue the [climate change] issue is more important for the south than the north …"
''If the issue is that Exxon have lobbied and pressured Bush, then OK, this is regrettable but to be honest is anyone really surprised? All these decision about IPCC chairs and co-chairs are deeply political … ''
Pauchari was elected chairman by a majority of countries and Watson was defeated. In 2007, under Pauchari, the IPPC handed down its next series of reports, not only confirming the 2001 findings on global warming but strengthening them.
''Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level,'' the first of the 2007 reports stated bluntly.
More significantly, the new report found that most of the increase in warming since the mid 20th century is, ''very likely'' due to a human-caused increase in greenhouse gas concentrations. After Pauchari accepted the Nobel Prize on behalf of the IPPC, the Indian engineer once favoured by the Bush White House became the object of attack by global warming sceptics.
IN recent weeks, with climate science and scientists again under siege in the media, on sceptic blogs and from critics within their own ranks, the hacked East Anglia emails are a timely reminder that the so-called science ''war'' over global warming is nothing new.
The credibility of the IPPC and some of the high-profile individuals who contribute to it have come under attack after every report. The attacks often escalate just before the crucial UN meetings of government ministers, which follow the reports that are supposed to debate how to cut global greenhouse gases. From Kyoto in 1997 to Copenhagen in 2009, climate sceptics and industry critics have targeted the science's credibility and challenged the need to cut greenhouse gases.
The hacked East Anglia emails were posted on sceptic websites just weeks before December's Copenhagen climate conference. The arguments against the climate science, even though supercharged by the emails, had little immediate effect on the UN conference. But the emails' content is affecting public opinion in Britain and most likely the US and Australia.
They revealed the private efforts by the IPPC author and the former director of the East Anglia Climate Research Unit, Jones, to blunt the sceptics' scrutiny of some of his early temperature research and argue against FOI requests for this data. The unvarnished comments in some of the emails from Jones have damaged the reputation of the world's leading climate research units.
The IPPC was drawn into the crisis when a British science reporter picked up a howling error in one of the critical 2007 reports handed down under Pauchari. The error was not contained in the scientific findings of observed climate change or its advice to government, but in a 938-page report on the impacts of warming.
That report included a reference to a claim that the Himalayan glaciers could melt by 2035. The IPPC and Pauchari compounded the error, many believe, by their slowness to issue a correction.
But despite the crisis engulfing climate science in recent weeks, no serious scientific academy, university or government research agency around the world is disputing the IPPC's core findings: that global average temperatures have been increasing and that human activity is very likely responsible because of the burning fossil fuels and deforestation, which is increasing greenhouse gas concentrations in the atmosphere.
''The hacking of the emails will have zero impact on the scientific case for climate change,'' says Will Steffen, the head of the Australian National University's Climate Change Institute.
While he acknowledges that some of Jones's temperature data was questioned in the hacked emails, Steffen points to thousands of studies across all the scientific disciplines over recent years that have supported the IPPC's findings on global warming.
''There is an enormous amount of evidence from the recent warming of the planet beyond the instrumental atmospheric temperature record,'' says Steffen, who authored a report on the issue last year for the Department of Climate Change.
''This evidence includes rising ocean temperatures, reductions in Arctic sea-ice thickness and extent, the melting of permafrost, the satellite measurements of rising atmospheric temperature, the loss of ice mass in Greenland, and more recently Antarctica, and thousands of ecological case studies on land and in the ocean showing changing times for ecological events like the flowering of plants and mating of organisms, the migration of fish, plants, birds and many others in response to the warming environment.''
Few non-scientists realise that the IPPC does not produce its own original scientific research on global warming but draws on the work of scientists from all over the world. Critical parts of the core scientific evidence have been researched by Australian scientists and Steffen, like his colleagues, is concerned that the battering of the IPCC, and climate science in general, could undermine the key scientific institutions in Australia doing this work.
''An attack on the trust and credentials of Australian and global climate science is an attack on the fundamental scientific institutions. In an Australian context, what we are are talking about are the major research and observations institutions - CSIRO, the Bureau of Meteorology and the leading Australian universities. There has to be a high level of trust in these institutions on the part of the public,'' he says.
But a number of Australian scientists who spoke to the Herald are worried the crisis will undermine public confidence in climate science.
These concerns are compounded by what many viewed as the failure of world leaders to reach agreement in Copenhagen to cut global greenhouse gases. Add to this the exceptionally cold winter in parts of Britain and North America and the net result is that the public's clamouring for early action on climate change has been muted.
But while Republican sceptics in Washington are Twittering that, ''It's going to keep snowing in DC until Al Gore cries uncle'', climate scientists are again reminding the public not to confuse the local weather with the global climate.
The winter in Washington might be brutal this season but the latest figures from NASA's Goddard Institute for Space Studies show last year, globally, was the second warmest year since modern records began in 1880 and the decade beginning January 2000 was the warmest decade.
There is much speculation in Canberra that the science crisis will favour the Opposition Leader, Tony Abbott and sceptics in his party. But in the US key figures in the Obama administration are more sanguine about its long-term impact.
This week the UN Climate Envoy, Todd Stern, at his first big public appearance since Copenhagen, was asked about the impact of ''Climategate''. Stern, who first represented the Clinton administration at Kyoto in 1997, was unfazed.
''The fundamental science on this issue is quite clear and mounting evidence on the ground of what is actually happening and growing sophistication of the modelling goes way beyond any particular set of data or any particular problems that occurred with respect to East Anglia or the IPCC mistakes,'' Stern said.
Marian Wilkinson is the Herald's environment editor