Page - 4 - in options, Volume winter 2016/2017

research news 4 options + winter 2016/2017 www.iiasa.ac.at iiasa research Country pledges overshoot Paris limits Pledges made for the Paris Agreement on climate change last winter would lead to a global temperature rise of 2.6 to 3.1°C by the end of the century. In fact, the entire carbon budget for limiting warming to below 2°C might have been emitted by 2030, according to a study published in the journal Nature. “The Paris Agreement was a historical achievement for the world’s response to climate change. It puts in place a flexible framework for a long‑term transformation towards a low‑carbon society. However, the optimism accompanying the agreement’s entry into force has to be carefully balanced against the important challenges that lie  ahead; emission reduction measures need strengthening to keep warming to well below 2°C, let alone 1.5°C,” says IIASA researcher Joeri Rogelj, who led the study. The study provides an in‑depth analysis of the emissions reduction pledges which countries submitted at the Paris climate meeting in December 2015. In order to assess what would happen after the pledge period ends in 2030, the researchers assumed that emissions reduction efforts would be continued at the same level of effort. The study also found major uncertainties in both the amount of emissions reductions that the pledges will lead to, and how much temperature will rise in response to given levels of emissions. Rogelj  points out that of the two, only the uncertainty in pledges can be reduced. “If we want to keep 2°C within reach, we’ll need much more rapid and fundamental changes,” says IIASA Energy Program Director Keywan Riahi. KL Further info Rogelj J, den Elzen M, Höhne N, Fransen T, Fekete H, et al. (2016). Paris Agreement climate proposals need a boost to keep warming well below 2°C. Nature 534(7609):631–639 [pure.iiasa.ac.at/13307]. Joeri Rogelj rogelj@iiasa.ac.at To wipe out a disease: model the costs Efforts to eradicate a disease are likely to fail if medical professionals cannot predict how costs will develop as the eradication effort progresses, according to recent IIASA research. The study examined the interplay between human population structure, disease evolution, and economic factors to determine how diseases can be controlled, using a new, model‑based view of disease eradication. Most of the world’s deadly illnesses have survived efforts to eradicate them, resurging in vulnerable populations and in some cases gaining resistance to standard treatment. Malaria, for instance, again infected over 200 million people in 2010, according to the World Health Organization. “The problem with disease eradication is that it’s easy to make progress at the beginning, when you get big decreases in incidence. But then you reach the point when only a few cases pop up here and there. Once you get to this eradication end‑game, it becomes very difficult to make further progress,” says IIASA researcher Rupert Mazzucco. The reasons for this are multiple and interconnected, the study showed: Evolution may counteract eradication efforts; the way human populations are structured plays a role in disease spread; and economic factors contribute as well—if the political will to keep funding interventions wanes, the disease may come back. “Most research today in epidemiology comes from an on‑the‑ground view of specific disease data. This study shows that a model‑based perspective on disease eradication can provide useful information for public health institutions aiming to eradicate diseases,” says IIASA Evolution and Ecology Program Director Ulf  Dieckmann. KL Further info Mazzucco R, Dieckmann U, Metz JAJ (2016). Epidemiological, evolutionary, and economic determinants of eradication tails. Journal of Theoretical Biology 405:58–65 [pure.iiasa.ac.at/12816]. Rupert Mazzucco mazzucco@iiasa.ac.at