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Halfway There? The Land Sector’s Contribution to Closing the Emissions Gap

To mitigate or not to mitigate?

To mitigate or not to mitigate?

A new report by the Union of Concerned Scientists summarizes the current state of knowledgde on the potential for climate change mitigation in the agricultural, forestry and other land use sectors: Half or more of emissions reductions needed to keep global temperature rise under 2 degrees could come from land sectors of major emitting countries.

The total mitigation potential in the land sector world wide is up to 13 Gt CO2eq per year, of which only eight countries – Brazil, China, the Democratic Republic of the Congo, the European Union, India, Indonesia, Mexico, and the United States can contribute around 7 Gt Co2eq/year. This would be 76% of the emissions gap in 2020 and 44% in 2030.

An interesting aspect of such estimates of mitigation potentials is that they assume carbon prices of up to $100 per ton. At this, it is difficult to imagine that only emissions from the land use sector would be taxed from climate policies, Rather, such policies would also and primarily involve the energy sector. This by itself would already bring down emissions and reduce the demands for mitigation from the land use sector. Indeed, recent results from a comprehensive climate policy study suggest that with average carbon prices of at most $60 over the period to 2100 and the use of adequate technologies, the land use sector would have to contribute only about 1.1 GtCO2eq/year if a 2 degree target is to be attained.

So, the sector’s potential for greenhouse gas mitigation should be more than sufficient.

RCPs, SSPs, SPAs, …. what????

At the latest with the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) a number of new acronyms started spilling out of the climate change research community to policy makers and the broader interested public. Centrally among them are RCPs, SSPs and SPAs, meaning Representative Concentration Pathways, Shared Socio-economic Pathways and Shared climate Policy Assumptions, respectively.

But what is this all about? And where do I have to look if I need more detailed information?

A nice and user-friendly introduction to the scenario framework is given at the IIASA website.

A first more detailed reference certainly is the article on A new scenario framework for Climate Change Research which forms part of a special issue A Framework for the Development of New Socio-economic Scenarios for Climate Change Research of the journal Climatic Change. The paper describes the basic concept how scenarios  that take into account the two dimensions of future climate change and socio-economic development can be formulated by combining alternative levels of radiative forcing of the climate system, described by RCPs, with alternative trajectories of future global development, described by the SSPs.

It also lines out that givens levels of radiative forcing may be attained through different climate policy designs and that different pathways of socio-economic development may require different sets of policies. This is the point where the SPAs come in, which complete the three-dimensional scenario framework.

For descriptions of the Shared Socio-economic Pathways (SSPs), another paper in the same special issue is worth reading. Details on the narratives that underlie each of the SSPs can be found in a workshop report on The Nature and Use of New Socioeconomic Pathways for Climate Change Research. The core data sets with pathways of economic growth and population growth for each SSP are accessible through the SSP Database.

The Representative Concentration Pathways (RCPs)  are dealt with extensively in another special issue on The Representative Concentration Pathways in Climatic Change. The articles in this collection give an overview on the RCPs and details on each of the RCPs that are used for the scenario framework.

The concept of Shared Policy Assumptions (SPAs)  is introduced  in a paper, which provides details on the concept and how it links into the general scenario framework.

As a nice feature, most of the information is open access.