IPCC report warns greenhouse gas levels at highest point in 800,000 years, identifies fossil fuels as cause of recent increases

Updated

The world's top scientists have given their clearest warning yet of the severe and irreversible impacts of climate change.

The United Nations Intergovernmental Panel on Climate Change (IPCC) has released its synthesis report, a summary of its last three reports.

It warns greenhouse gas levels are at their highest they have been in 800,000 years, with recent increases mostly due to the burning of fossil fuels.

"Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems," the report said.

"Limiting climate change would require substantial and sustained reductions in greenhouse gas emissions which, together with adaptation, can limit climate change risks."

IPCC chairman Rajendra Pachauri said the comprehensive report brings together "all the pieces of the puzzle" in climate research and predictions.

"It's not discrete, and [highlights] distinct elements of climate change that people have to deal with, but [also] how you might be able to deal with this problem on a comprehensive basis by understanding how these pieces of the puzzle actually come together," Dr Pachauri said.

The report reiterates that the planet is unequivocally warming, that burning fossil fuels is significantly increasing greenhouse gas emissions and the effects of climate change - like sea level rises - are already being felt.

IPCC synthesis reports' findings: In its first assessment in 1990, the IPCC said observed temperature increases were "broadly consistent with predictions of climate models, but it is also of the same magnitude as natural climate variability".

The second assessment, in 1995, said: "Results indicate that the observed trend in global mean temperature over the past 100 years is unlikely to be entirely natural in origin."

In 2001, its third assessment reported: "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities."

By 2007, the consensus had reached "very high confidence" – at least a 90 per cent chance of being correct – in scientists' understanding of how human activities are causing warming.

This fifth assessment puts that certainty at 95 per cent and noted "recent climate changes have had widespread impacts on human and natural systems". Source: IPCC

It also said most of the world's electricity should be produced from low carbon sources by 2050 and that fossil fuel burning for power should be virtually stopped by the end of the century.

Last month Prime Minister Tony Abbott said coal is "good for humanity" and will be the "world's main energy source for decades to come" as he opened a new mine in central Queensland.

IPCC vice-chair Jean-Pascale van Ypersele said while Mr Abbott was correct to point out the world could not end its reliance on fossil fuels for energy immediately, change was necessary.

"The continued usage of fossil fuel could damage not only the environment but more substantially even the habitability of the planet and could erode the possibility to keep this planet habitable," he said.

"He's right, but the IPCC is right as well, and this is why climate negotiations, where the different bits of information including about the importance of energy in development, need to be taken into account and that's also why the climate negotiations are so difficult.

"Energy is important for development but clean energy is important for protecting [the] climate."

Environment Minister Greg Hunt said the Government's Emissions Reduction Fund - part of its Direct Action climate change policy which passed the Senate last week - will ensure power stations are cleaner.

"The work that the CSIRO is doing is looking at a 30 to potentially 50 per cent reduction in the footprint of coal fired power stations," he said.

"The world needs to ensure there's electricity for those that are trying to work their way out of poverty, that's been the great goal and dream of humanity for centuries."

Dr Pachauri said in several respects Australia was "very vulnerable to the impacts of climate change".

"It also has the means by which you can implement several measures," he said.

"I've always admired the amount of work that Australia has done in the field of solar energy, I hope that will be built on because that will have major benefits for society across the globe."

Australian expert says warming of climate system 'unequivocal'

Australian oceans expert John Church was in Copenhagen to negotiate the final wording of the report.

Dr Church was the coordinating lead author of the sea levels chapter and said warming of the climate system is "unequivocal".

"There's many components - increasing surface temperature, melting glaciers, increasing ocean heat content, ice sheets losing mass, sea level rising," he said.

"It's very clear that there's a human component that's contributed significantly to that with rising impacts across many regions."

The document will be an invaluable summary for climate negotiations for emission reduction targets post-2020.

Mr Hunt said increasing ocean acidification also has him concerned.

"All up the best advice that I have is that we've seen a 25 per cent increase in acidity over the last 250-odd years," he said.

"We don't know what impact these changes will have. We do know that the impact on marine animals with shells is significant, it could have a long-term impact and for me this is one of the most powerful findings of the report."

'Energy sector has sought to become more sustainable'

The New South Wales Minerals Council chief executive Stephen Galilee said phasing out the burning of fossil fuels for power over a short period of time will have social and economic consequences.

"The idea that you'll be able to withdraw fossil fuels from the energy mix over a relatively short period of time is one that really deserves serious investigation because it's going to cause significant social and economic dislocation," he told the AM program.

"There's a pretty strong recognition that people need energy for their own lifestyle and for their own future.

"And as long as we as an industry can demonstrate that we are operating responsibility and meeting our obligations along with all the other industries that need to do the same, I think that we will continue to enjoy the support of the community that we do here in NSW and more broadly."

Mr Galilee said the energy sector had taken steps to ensure it was sustainable.

"We've been reducing our impacts, we've been reducing our emissions, we've been investing in technology," he said.

"The Australian coal industry is the only coal industry in Australia that has been voluntarily investigating innovation technology over at least a decade or more to reduce our impact and to reduce our emissions and we're seeing the benefits of that."

Leaders must act, UN chief warns

UN secretary-general Ban Ki-moon said the report was the most comprehensive appraisal of climate change yet and that human influence was clear.

"Science has spoken, there is no ambiguity in their message," he said.

"The report found that the world is largely very ill-prepared for the risk of changing climate, especially the poor and most vulnerable, who have contributed least to this problem.

"Leaders must act. Time is not on our side."

One of the authors, Professor Jim Skea, said the document would be invaluable in future climate change negotiations.

"The statements are much more powerful because they're put together," he said.

"The inferences that you can draw are just very obvious for policymakers now and I think that's what the achievement is."

US secretary of state John Kerry said those who ignored climate science did so "at great risk for all of our kids and grandkids".

"The longer we are stuck in a debate over ideology and politics, the more the costs of inaction grow and grow," he said.

"We're seeing more and more extreme weather and climate events, whether it's storm surges, devastating heat waves, and torrential ran, across the globe. It's not a coincidence."

Governments will meet in Peru this year as part of the United Nations Framework Convention on Climate Change annual meeting.

Targets are expected to be finalised at the 2015 negotiations in Paris, but the Peru conference will serve as an important step forward in setting the framework.

Christina Figueres, who will lead the climate discussions in Paris, said it was encouraging that governments, cities, investors, companies and individuals had started to act in response to the IPCC's findings.

Foreign Minister Julie Bishop will lead Australia's negotiations next year in Paris.

Topics: greenhouse-gas, environmental-policy, environment, environmental-impact, environmental-management, australia, denmark

First posted