By environment reporter Sarah Clarke
ABC News Online, 15 March 2010
Download the new CSIRO/BoM report here - http://www.csiro.au/resources/State-of-the-Climate.html
The head of Australia's peak science body has spoken out in defence of climate scientists, saying the link between human activity and climate change is beyond doubt.
The head of the CSIRO, Dr Megan Clark, says the evidence of global warming is unquestionable, and in Australia it is backed by years of robust research.
Dr Clark says climate records are being broken every decade and all parts of the nation are warming.
"We are seeing significant evidence of a changing climate," she said.
"If we just take our temperature, all of Australia has experienced warming over the last 50 years. We are warming in every part of the country during every season and as each decade goes by, the records are being broken.
"We are also seeing fewer cold days so we are seeing some very significant long-term trends in Australia's climate."
Dr Clark says the long-term data across a number of measures stacks up in favour of climate change proponents and against those who say the planet is not warming.
"We can certainly look at the long-term trends and any event here or there or a storm here or there really doesn't explain away what we are seeing in these major long-term trends," she said.
"We are also seeing consistency. I think the consistency between our temperatures, what we are seeing in our rainfall, what we are seeing in the increase of carbon dioxide and methane in our atmosphere and of course, what we are now seeing in our oceans.
"So it is not just one measurement that is telling us. It is our observations and science that we are seeing in many areas being consistent."
Dr Clark says the evidence strongly suggests human activity is responsible for the rise.
"We know two things. We know that our CO2 has never risen so quickly. We are now starting to see CO2 and methane in the atmosphere at levels that we just haven't seen for the past 800,000 years, possibly even 20 million years," she said.
"We also know that that rapid increase that we've been measuring was at the same time that we saw the industrial revolution so it is very likely that these two are connected."
Dr Clark says scepticism is a healthy part of the scientific process and has been considered as part of the climate change debate.
But she says the data needs to be looked at in a systematic way and the evidence backs those who say humans are contributing to global warming.
"Whenever we come into groups with very complex issues as a society, every time we have done that, we should challenge and we do challenge and it brings us back to our observations," she said.
"It makes us re-look at what we are really seeing. It makes us ask those questions, so I think challenge is simply part of coming to understand an issue.
"But at the same time, plucking out a snow storm in the US or a flood in Queensland or a cold day somewhere and trying to use that to explain away some of these long-term trends, of course, we know is not the right way to do it."
Dr Clark says the data the CSIRO has based its conclusions on is both long-term and solid.
"We have been recording and the [weather] bureau has been recording our climate for over 100 years," she said.
"Our records here are extremely robust and of course, CSIRO is studying and researching and looking at those trends for over 50 years so I think we are very blessed in this country to have some very, very robust data and very long-term [data]."