The very big picture on climate change

15 April 2014

Two ANU experts have made a significant contribution to the IPCC's latest climate change report.

The senior researchers from Crawford School in the ANU College of Asia and the Pacific are lead authors in the world's most significant report on climate change policy, released 14 April.

Associate Professor Frank Jotzo and Professor David Stern were among the authors of two different chapters of the Intergovernmental Panel on Climate Change (IPCC) Working Group III report.

The global report assesses the options for mitigating climate change and maps out current and past knowledge on greenhouse gas emissions, their future paths, and policy efforts to reduce emissions.

It is produced every seven years and this time around involves 235 of the world's leading researchers. They cite almost 10,000 research papers, and responded to 38,000 expert comments.

Professor Stern says that global emissions have increased significantly in the past 10 years especially in middle-income countries.

"Global greenhouse gas emissions rose more rapidly between 2000 and 2010 than in the previous three decades and this is mainly because of rapid growth in emissions in middle-income countries like China.

"However, per capita emissions remain very unequal globally with emissions per capita in high-income countries averaging nine times the level in the lowest income countries," he said.

He added that the increase of carbon emissions is a clear indication that renewable energy technologies need to be adopted.

"The unequal distribution of per capita emissions means that there is a lot of scope for 'catch-up growth' in emissions under business as usual and points to the need to switch to low carbon energy sources as soon as possible.

"This is because the majority of emissions are derived from energy use and energy efficiency improvements have historically been insufficient to offset the growth in income per capita let alone population growth, especially in the decade 2000 to 2010," he said.

Associate Professor Frank Jotzo says that for the first time the report not only looks at the technical and economic issues of climate change but it also looks at the ethical questions and suggests what action needs to be taken to reduce climate change risks for future generations.

"This is the first time that the IPCC goes into the ethical underpinnings of the impacts and responses to climate change. This comes out of a realisation that climate change policy is ultimately about the values that we hold.

"Climate change poses deep moral dilemmas, and the nature of it as a long term global issue means that action needs to be predicated on a concern about future generations and the fate of people in other countries and societies.

"The report maps out issues that societies need to grapple with, and gives decision makers a compass to navigate their way," he said.

Jotzo said that the report's technical findings translate into ethical issues that need to be wrestled with.

"The analysis shows that unless very strong climate action is taken immediately, keeping warming to two degrees will require global emissions to become negative in the second half of the century, for example by burning biomass in power stations and capturing the carbon dioxide. Are we happy to leave future generations with such burdens and risks?

"To effectively address climate change, all major countries - including developing nations - need to act soon and decisively. But who should pay for the costs, and how to compare costs and benefits of climate change action across rich and poor societies? Species are threatened with extinction and there is a risk of runaway climate change - how do we weigh this against the cost of moving to a cleaner energy system?

"Definitive answers aren't given in the report, they're ultimately for each individual and society to form a view about, in line with their particular values."

Story by Amelia Bidgood.