The world may have to rely on “emissions-negative” energy technologies in the latter half of this century, according to the Intergovernmental Panel on Climate Change’s new report on reducing the impacts of climate change.
Swapping fossil fuels for plant material, and then burying the resulting carbon dioxide to avoid it entering the atmosphere, is the kind of tactic that could help put world greenhouse emissions into reverse, said report co-chair Ottmar Edenhofer, an economist at the Potsdam Institute of Climate Impact Research.
“If we can provide bioenergy in a carbon-neutral way, and also have the means to remove and store carbon, that would be a useful technology cluster,” Professor Edenhofer said.
However, he added that the world will need “a broad portfolio of options” if it is going to make deep enough emissions cuts to meet the internationally agreed target of limiting long-term warming to 2°C.
Those options include market-based solutions such as carbon pricing, moves towards renewable energies and other alternatives such as nuclear power, and other technological fixes that have yet to be widely deployed, such as carbon capture and storage.
Edenhofer stressed that the IPCC does not make policy recommendations, but rather sets out the options so that politicians can make informed decisions.
“When we talk about technologies like nuclear power we do not assume that there is an agreement between scientists, but what we can do is we can explain that if you want to meet these targets then you have to take into account specific costs and risks,” he said.
Edenhofer said the IPCC’s calculations suggested that limiting global warming to 2°C was likely to stunt world economic growth by between 1% and 5%, relative to its current rate.
Concerted action was needed to curb the current “business as usual” trajectory, he said. “We are not running out of fossil fuels, and we cannot expect that the fossil fuel market will solve the climate problem.”
Edenhofer also stressed the importance of international cooperation: “We can do a lot at the national scale, at the city scale, at the regional scale, but at the end of the day what we need is global agreement.”
Old and new technologies
Matt Watson, a senior lecturer in natural hazards at the University of Bristol, sounded a note of caution about techniques to capture carbon dioxide from the atmosphere:
Anyone that suggests carbon dioxide removal is a distraction and a potential moral hazard does not understand the extent to which these imaginaries are already embedded in climate scenarios and should also better consider the severity of the peril we face. Conversely, anyone touting carbon dioxide reduction technologies as a panacea is not being realistic about the cost and timescales involved in their deployment.
IPCC author Richard Harper, of Murdoch University, said the report shows how land-use changes can also contribute to curbing emissions.
“Basically, there are three ways the land can contribute to carbon management: by reducing emissions from existing carbon stocks (e.g. clearing forests) or agricultural activities; by increasing carbon stocks in soils or vegetation (carbon sinks); or by replacing fossil fuel emissions by burning biomass or using wood products,” he said.
Ethical considerations
For the first time, the IPCC has factored in ethical considerations, as well as economic ones, when considering emissions mitigation.
Glenn Albrecht, director of the Institute for Social Sustainability at Murdoch University, said:
“While global warming and consequent climate change are the subjects of increasing scientific investigation, our responses to such knowledge must lie within the realm of ethics. When the consensus on the accuracy of the science is near 100%, we must ask, why are we imposing such a massive risk of social, economic, industrial and agricultural disruption and failure on ourselves?”
Griffith University psychologist Joseph Reser said the issue was personal, as well as international.
“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,” he said.
The impact on Australia
Hugh Outhred, a senior visiting fellow at the University of New South Wales, said Australia is heavily dependent on fossil fuels for both energy and export.
“Australian society has demonstrated that it has the capability to take a leading role in developing and implementing low-emission technologies and adopting low-emission lifestyles. However, that seems unlikely given the present combative and ill‐informed political debate about climate change and the influence of the fossil fuel lobby,” he said.
Liz Hanna, a fellow of the National Centre for Epidemiology and Population Health at the Australian National University, described action on climate change as an “economic and moral imperative”.
“Delaying strong mitigation efforts lowers the likelihood that warming could be curtailed at 2 degrees. This wilful disregard for human safety should be recognised for what it is: short-term gain at the expense of a collective future in a world that is habitable.
"Delay also incurs increasingly prohibitive mitigation costs. Combined, these subject today’s children and young adults to a world where governments must spend more to mitigate, at a time when more extreme weather events necessitate higher costs on repairing infrastructure, and relocating vital services away from coastlines. Diminished funds will be available for health and education and nation building.”
These expert reactions were compiled with the help of the Australian Science Media Centre.