Major change required to curb climate change, says IPCC

The Intergovernmental Panel on Climate Change’s (IPCC) Working Group 3 has released its contribution to the Fifth Assessment Report.

The report, titled ‘Climate Change 2014: Mitigation of Climate Change’, finds that global emissions of greenhouse gases have risen to unprecedented levels, growing more quickly between 2000 and 2010 (2.2% per year) than in each of the three previous decades. Economic growth and population growth were the two main drivers of recent increases in CO₂ emissions from fossil fuel combustion, outpacing gains from producing and using energy more efficiently.

The report says it would be possible, using a wide array of technological measures and changes in behaviour, to limit CO₂-e concentrations in 2100 to about 450 ppm and the mean global temperature change at 2°C above pre-industrial levels. However, only major institutional and technological change will give a better than even chance that global warming will not exceed this threshold.

“Climate policies in line with the 2°C goal need to aim for substantial emission reductions,” said Working Group 3 co-chair Ottmar Edenhofer. “There is a clear message from science: To avoid dangerous interference with the climate system, we need to move away from business as usual.”

Scenarios show that limiting the increase to 2°C means lowering global greenhouse gas emissions by 40 to 70% compared with 2010 levels by mid-century, and to near-zero by the end of this century. Scientific literature confirms that even less ambitious temperature goals would still require similar emissions reductions.

About 1200 scenarios from scientific literature were analysed in order to explore the economic, technological and institutional prerequisites and implications of mitigation pathways with different degrees of ambition. According to Edenhofer, “Many different pathways lead to a future within the boundaries set by the 2°C goal. All of these require substantial investments.”

Stabilising greenhouse gas concentrations in the atmosphere requires emissions reductions from various sectors, with mitigation efforts in one sector determining the needs in others. And while cutting emissions from electricity production to near zero is a common feature of ambitious mitigation scenarios, using energy efficiently is also important.

“Reducing energy use would give us more flexibility in the choice of low-carbon energy technologies, now and in the future,” said co-chair Ramón Pichs-Madruga. “It can also increase the cost-effectiveness of mitigation measures.”

Land is another key component for the 2°C goal. Slowing deforestation and planting forests have stopped or even reversed the increase in emissions from land use. Through afforestation, land could be used to draw carbon dioxide from the atmosphere. This could also be achieved by combining electricity production from biomass and carbon dioxide capture and storage.

“The core task of climate change mitigation is decoupling greenhouse gas emissions from the growth of economies and population,” said co-chair Youba Sokona. “Through providing energy access and reducing local air pollution, many mitigation measures can contribute to sustainable development.”

“International cooperation is key for achieving mitigation goals,” said Edenhofer. “Putting in place the international institutions needed for cooperation is a challenge in itself.”

Several independent experts have provided their thoughts on the report. Professor Glenn Albrecht, director of the Institute for Social Sustainability at Murdoch University, asks people to consider the ethical implications of the report.

“Why are we imposing such a massive risk of social, economic, industrial and agricultural disruption and failure on ourselves?” Professor Albrecht said. “The ethics of greenhouse gas mitigation require all nations and people to reduce greenhouse gas emissions to levels that will deliver a safer world for all.

“We must invest ethically and economically in a new era where we make a just and equitable transition to non-polluting, renewable energy sources.”

Professor Joseph Reser, from the School of Applied Psychology at Griffith University, took the issue down to a personal level, noting “many crucial considerations relating to the human dimensions and impacts of climate change have not been on the radar of climate change science”.

“Personal engagement with the issue and ‘taking action’ in the context of one’s own lifestyle and circumstances can play crucial roles and provide multiple benefits in addition to reducing one’s carbon footprint. Being engaged and doing something helps people to come to terms with the reality and implications of climate change, and feel that they are making a difference, being informed and responsible, and part of the solution and not just the collective problem.”

Dr Liz Hanna, president of the Climate and Health Alliance, claims that governments around the world have “failed”, stating that they have wasted “time that we simply do not have”.

Scenarios without additional mitigation were found to result in global mean surface temperature increases in 2100 from 3.7 to 4.8°C compared to pre-industrial levels. “This warming is not compatible with human existence,” Dr Hanna said, citing not just the rising temperature itself but the weather extremes that it brings.

Professor Susan Krumdieck, from the University of Canterbury, said, “Who in the world would say that, as a matter of convenience, we should push essential systems to collapse?

“The only option now is for all responsible, competent and sensible people to demand action from engineers, planners and business leaders to change every system that produces and uses climate-affecting materials to dramatically reduce the production and use of fossil fuels and reduce the emissions of other greenhouse gases.”

The report can be viewed at http://ipcc.ch/report/ar5/wg3/.