13 April 2018

The 1.5°C target can also be met using less negative emissions

Alternatieve scenario's

The objectives of the Paris Climate Change Agreement can be attained with less negative emissions than shown in the majority of analyses. A greater focus on lifestyle change, increased use of renewable energy and a substantial reduction of methane emissions are alternatives to negative emission efforts such as bioenergy in combination with CO2 capture and storage (BECCS). While it is not possible to reduce negative emissions to zero, the use of BECCS can be scaled down significantly.

Researchers from Utrecht University and PBL Netherlands Environmental Assessment Agency draw these conclusions in an article in Nature Climate Change. Studies into the objectives of the Paris Agreement usually indicate that, in addition to rapid emission reductions, there is also a need for large-scale negative emission efforts, such as reforestation and bioenergy with CO2 capture and storage. Many negative emission efforts require substantial areas of land, which may have consequences for the global food supply and for nature. Using the IMAGE model, PBL and Utrecht University have now elaborated alternative paths to achieve the objectives of the Paris Agreement.

Negative emissions lead to extensive land us

The Paris Agreement aims to limit the global temperature rise to well below 2°C, and preferably to 1.5°C. This objective requires a considerable reduction in greenhouse gas emissions. Therefore, scenarios focussing on the Paris target almost always involve methods to remove CO2 from the atmosphere, the so-called negative emissions. When considering negative emissions needed at the end of the century, calculations quite often result in amounts that are so large that they can have negative consequences for food supply or nature. The question is whether these can be limited.

Exploring alternative scenarios with computer models

It is possible to explore alternative scenarios by using computer models. Normally, the models are mainly used to find the best possible combination of measures to meet the climate target. In this study however, researchers from PBL and Utrecht University explore all sorts of alternative scenarios that could lead to less negative emissions. This involves, for example, lifestyle change, additional reduction of non-CO2 greenhouse gases such as methane, and increased use of renewable energy.

Negatieve emissies leiden tot veel landgebruik
Negative emissions lead to extensive land us

Achieving less negative emissions is possible, but not down to zero

The new IMAGE scenarios show that there are several paths towards achieving the 1.5°C target. This provides more flexibility as to the formulation of policies. Most of the new scenarios depend less on negative emissions than the default solution. One of the assumptions in the lifestyle-change scenario is a reduction of meat consumption to the level that is recommended for a healthy human diet. This leads to a decline in methane emissions from cows and the freeing up of land that is now used to produce animal feed. These areas may be used for reforestation or bioenergy production. However, the scenarios also show that it is wise to continue to develop technology for negative emissions.

Exploring the pros and cons

"We can use the results to compare the advantages and disadvantages of the standard scenario with those of the alternatives", says Detlef van Vuuren, project manager of the IMAGE project and professor at Utrecht University. "It is clear that each path comes with its own challenges. For example, a change in dietary habits entails a large-scale change in the global food system. In any case, each scenario shows a clear break with past trends". Many of the alternative scenarios do seem to be compatible with reaching other UN sustainability goals, such as those related to nature, the global food supply and health. "This is important in order to increase social support for far-reaching climate policies. In developing countries in particular, the agenda of the Sustainable Development Goals is just as important for the future as climate policy", Van Vuuren adds.

Article

Detlef P. van Vuuren Elke Stehfest, David E. H. J. Gernaat, Maarten van den Berg, David L. Bijl, Harmen Sytze de Boer, Vassilis Daioglou, Jonathan C. Doelman, Oreane Y. Edelenbosch, Mathijs Harmsen, Andries F. Hof and Mariësse A. E. van Sluisveld (2018). Alternative pathways to the 1.5°C target reduce the need for negative emission technologies. Nature Climate Change.