Apr 9, 2014 | Energy & Climate, Science and Policy
By Matthias Jonas, IIASA, and Gregg Marland, Appalachian State University
Greenhouse gas emissions are seldom measured directly. They must be estimated from data such as on energy use and changes in land use. That means that estimates of greenhouse gas emissions from human sources are inherently uncertain.
Uncertainty around emissions may mean that reaching temperature targets would require greater cuts than previously thought. Central and Eastern Europe at night, taken from the NASA, International Space Station in 2011. Image Credit: NASA
In a new study with colleagues at IIASA and the Polish Academy of Sciences, we asked how uncertainty over time will affect short-term GHG emission commitments and long-term efforts to meet global temperature targets for 2050 and beyond. The new study addresses a fundamental problem: how to combine uncertainty about current and historic emissions (diagnostic uncertainty) with uncertainty about projected future emissions (prognostic uncertainty).
The paper introduces a concept we call the Emissions, Temperature, Uncertainty (ETU) framework.The ETU framework allows any country to understand its national and near-term mitigation and adaptation efforts in a more realistic context, where uncertainty is taken into account.
The ETU assumes that cumulative emissions can be constrained over time by international agreements that are binding, but that emissions can be estimated only imprecisely, and whether or not they will achieve an agreed temperature target is also uncertain. The ETU framework allows policymakers to understand diagnostic and prognostic uncertainty so that they can make more educated (precautionary) decisions for reducing emissions given an agreed future temperature target.
Diagnostic uncertainty refers to the uncertainty contained in current inventoried emission estimates and relates to the risk that true greenhouse gas emissions are greater than inventoried emission estimates. Prognostic uncertainty refers to cumulative emissions between a start year and a future target year and the global average temperature increase they would generate. It relates to the risk that an agreed temperature target is exceeded. In a nutshell, the ETU framework can be used to monitor a country’s performance – that is, past achievements as well as projected achievements – in complying with a future warming target in a quantified uncertainty-risk context.
While our study addresses whether or not the future increase in global temperature can be kept below 2, 3, or 4ºC targets, its primary aim is to use those targets to demonstrate the relevance of both diagnostic and prognostic uncertainty. The paper shows:
- Uncertainty is important in emissions: Both diagnostic and prognostic uncertainty need to be considered to facilitate better decisions on reducing emissions, given an agreed future temperature target.
- What these risks mean for emissions targets: We find, for example, that to nullify the diagnostic uncertainty-related risk, and to maintain a similar level of risk for exceeding a 2o target, the universally valid per-capita emissions target for 2050 resulting from the underlying cumulative emissions constraint needs to be shifted downward by nearly 10%.
- Risk and uncertainty are interdependent: This interdependence poses a challenge for decision-makers because they have to deal with uncertainty and risk simultaneously.
- Including land-use change is tricky: Determining cumulative emissions from land use and land-use change in this emission-temperature setting is difficult, because an achievable future state of sustainability for the terrestrial biosphere has not yet been defined.
Reference
Matthias Jonas, Gregg Marland, Volker Krey, Fabian Wagner, Zbigniew Nahorski (2014). Uncertainty in an emissions-constrained world. Climatic Change. April 2014. http://link.springer.com/article/10.1007/s10584-014-1103-6
Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.
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Mar 26, 2014 | Energy & Climate, Risk and resilience
By Reinhard Mechler, IIASA Risk, Policy, and Vulnerability Program
On March 25, member countries of the Intergovernmental Panel on Climate Change (IPCC) started discussing the key findings of the second volume of the Fifth Assessment Report (AR5) in Yokohama, Japan. The report focuses on climate-related impacts, risks and adaptation. Once approved by the 150+ governments present, together with IPCC’s other two parts of the report on physical climate science and mitigating greenhouse gases, it will constitute the scientific backbone for informing national and international climate policy over the coming years.
Flooded marketplace in Jakarta. Credit: Charles Wiriawan/Flickr (Creative Commons License)
A key aspect in climate adaptation is dealing with extreme events including natural disasters. It has become clear that extreme event risk constitutes a large part of the adaptation problem, particularly for developing countries and communities.
Despite this growing awareness, the international adaptation policy process is moving forward only slowly. Specifically, there is need for concrete advice for the Loss and Damage Mechanism, the main vehicle under the Climate Convention for dealing with climate-related impacts, which was agreed in Warsaw at the last Conference of the Parties in late 2013
In our commentary, published today in Nature Climate Change with colleagues from LSE, IVM and Deltares, we suggest that better understanding climate-related disaster risk and risk management can inform effective action on climate adaptation and point a way forward for policy and practice.
A key to moving forward is an actionable concept of risk. This involves identifying efficient and acceptable interventions based on recurrency of hazards—a concept known as risk layering. For example, for flood risk, this could mean identifying physical flood protection to deal with more frequent events, considering risk financing for infrequent disasters as well as relying on public and international compensation for extreme catastrophes. Risk layering overall points towards considering risk comprehensively as determined by climatic and non-climatic factors as well as considering portfolios of options that manage risks today and in the future.
The concept of risk layering underlies many areas of risk policy and management in agriculture, finance and insurance. It has been applied for disaster risks, mostly for insurance options, but not informed thinking on comprehensive risk management portfolios. Such broad understanding of risk management can also be helpful in identifying risks that are beyond adaptation–meriting international support, such as from the Green Climate Fund.
Climate risk management has now moved beyond theory. As one example, the megacity of Jakarta currently is setting up a multi-billion dollar program to manage increasing risk from sea level rise with large levees. This effort is integrated with a concern for managing flood risk and land subsidence, which are shaped by non-climatic factors, such as unplanned urbanization. The effort, therefore, involves options to implement acceptable building and zoning regulations for reducing exposure and vulnerability of houses and infrastructure to flooding.
Many policy-and implementation-specific questions remain. Over the coming months, IIASA researchers and our network will take the agenda on climate risk management forward with a focus on informing policy as well as providing actionable information on the ground.
Reference
Reinhard Mechler, Laurens M. Bouwer, Joanne Linnerooth-Bayer, Stefan Hochrainer-Stigler, Jeroen C. J. H. Aerts, Swenja Surminski & Keith Williges. 2014. Managing unnatural disaster risk from climate extremes. Nature Climate Change. March 26, 2014. http://www.nature.com/nclimate/journal/v4/n4/full/nclimate2137.html
Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.
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Nov 7, 2013 | Energy & Climate, Science and Policy
Peter Lemke, head of the Climate Sciences Research Division at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany, is an expert on sea ice, a polar explorer, and the Chair of the IIASA Council. In this interview Lemke explains how climate change is affecting the Earth’s polar regions, and talks about a recent winter expedition to Antarctica.
On Monday, 11 November Lemke will give a public lecture on the topic at IIASA in Laxenburg.
Peter Lemke – Credit: Stephanie von Neuhoff (AWI)
How did you get interested in the cryosphere? What drew you to the poles?
When I was a young scientist, I was involved in climate modeling and especially the role of polar regions. For my PhD thesis I worked on sea ice extent data, trying to understand why we see changes.
That was in the late seventies, so it was not really climate change which was driving us, we just wanted to understand the climate system. Polar regions are an important part of the climate system. We tried to understand how they impact the other regions on the globe such as mid-latitudes and even the tropics.
When did you realize that climate change was affecting the polar regions?
Well the globe was already warming when I was starting my research in the mid-1970s. Sea ice was decreasing in extent, and ice was melting on the continents. Year by year, this trend became more significant. By the 1990s it was quite clear that there was a trend which was not just natural variation. The third IPCC report in 2001 just made it clear that man had an impact on the warming; at least a substantial part of it was due to increased greenhouse gases in our atmosphere.
A helicopter that was used to measure sea ice during Lemke’s 2013 Antarctic expedition. Credit: Peter Lemke (AWI)
What is happening now?
The changes we see now are even more dramatic than before, especially considering the Arctic sea ice. It hit a record low minimum in 2007 and we thought that this was the ultimate—as low as it would go. But then ice extent went even lower in 2012. While the ice extent this last summer was not quite so low, there is a strong trend in summer extent of sea ice. Our data indicate that it’s not just the extent but the thickness that’s changing. Measurements of sea ice thickness which our institute has performed over the last decade or so show a sharp thinning of the sea ice in the interior of the Arctic: The sea ice has thinned from an average of 2.5 to about 1 meter in only 10 years.
The other thing that is interesting is that the sea ice extent in the Antarctic is not decreasing at the same rate. On the contrary, it’s increasing in extent slightly. The question is of course is the ice mass also increasing, or is it just spreading out and thinning—like a dough that you roll out, getting wider but thinner?
How do you explain the growth in Antarctic sea ice, while Arctic sea ice is declining?
One explanation is that in the Southern Hemisphere the westerly winds are increasing, and through friction this drives the ice towards lower latitudes and the extent is getting a bit bigger. When the ice expands there is open water between ice floes, and it’s still cold enough in winter that ice freezes in the open patches.
There are other physical processes that may be involved, such as the heavy snow cover that blankets the Antarctic sea ice. Sometimes the heavy snow load submerges the ice floe underwater so that the interface of ice and snow is actually below sea level, and seawater drains into the snow and freezes. That may be one process, but there are others that are not really resolved yet.
We don’t yet have the answers to these questions, because there are very few measurements and you cannot deduce snow from satellite remote sensing data, yet. To find out, you have to go there and make measurements yourself. But winter expeditions are very rare. There are very few icebreakers that can actually go into the Antarctic winter into the sea ice. I have participated in four expeditions over the last 25 years: in 1989, 1992, 2006, and now 2013.
Working site during the 2013 Antarctic expedition. The wind chill was often between -50 and -60°C. Credit: Peter Lemke (AWI)
What did you find on your latest expedition?
Most of the data have yet to be analyzed. But from our early results, it looks like that the sea ice mass around Antarctica has increased slightly. Our measurements showed that the sea ice was more extensive, thicker and more densely packed as compared to our 1992 expedition, which was on the same track during the same season.
We have also observed a continuous warming in the deep ocean, which indicates that the warming trend that we see over the last couple decades is continuing. This indicates that the ocean has taken up a large fraction of the heat due to the increased greenhouse effect.
Why should people care what happens in the Arctic or in Antarctica?
Both polar regions are pristine regions not affected by humans as much as lower latitudes. Still you see the effects of mankind there. Once the sea ice is gone in the Arctic, we have lost an entire ecosystem which is adapted to the sea ice. Sea ice is a porous medium, and in the small cavities, there is rich life—tiny algae, crabs, krill—and this ecosystem supports an entire food chain up to the polar bear, whales, penguins that you find depending on which pole you are looking at.
Do you think that IIASA has a role to play in polar research?
IIASA is currently considering a new Arctic initiative, which could involve not just the climate system and the ecosystem but also the human system. Changes in the Arctic are already affecting people living at the coastlines. This coastline is made up of sand and ice, which is thawing. And as the sea ice is retreating, the coastline is now exposed to the increasing waves in the open ocean. Already now villages are already eaten up by the sea. At the same time, hunting grounds are changing for Inuit and other indigenous people who rely on sea ice for hunting. I think that’s something that IIASA can actually look at from a holistic view: human system, ecosystem, climate system.
What is one thing you want people to know?
Well often the poles, especially the Arctic, seem so far away that people don’t think that it is important for their lives. But if you have a polar storm coming from Svalbard, within two days it reaches the German coast, and within 10 days the entire Northern Hemisphere may be affected. The Arctic is only a few days away from us, and conditions that are changing in the Arctic will affect the climate conditions also in our region.
Emperor penguins spotted during Lemke’s 2013 Antarctic expedition. Credit: Peter Lemke (AWI)
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Oct 29, 2013 | Energy & Climate, Science and Policy
This post was originally published on the recharge.green blog. IIASA is a partner in the new project, which focuses on the potential for renewable energy in the Alps.
When I think of an alpine forest, I think of the towering cedar trees that blanket the Cascade mountains near my native Seattle, with trunks so broad you can’t reach your arms around them. I think of the shadowy quiet that envelops me as I wander through a mountain forest in my new home in Austria. I think of the scent of pine needles and the bounce of my feet on a trail softened by forest litter. The value of a mature forest to people like me who love the outdoors—its recreational value—is impossible to put into numbers.
We can, however, calculate the effects of different styles of forest management on more quantifiable criteria. We can determine how much carbon dioxide is taken up from the atmosphere and stored by long-growing forests. And we can estimate how much bioenergy we can sustainably produce by managing forests for biomass harvesting.
This is exactly what IIASA scientists have done for their first efforts in the recharge.green project. IIASA’s role in the project is to use our modeling expertise to explore the various possibilities for renewable energy expansion in the Alps. We are also looking at the tradeoffs and benefits of the different possible scenarios and ecosystem services (ESS). As a first step, researchers Florian Kraxner, Sylvain Leduc , Sabine Fuss (now with MCC Berlin), Nicklas Forsell, and Georg Kindermann used the IIASA BeWhere and Global Forest (G4M) models look at the tradeoffs between bioenergy production or carbon storage in alpine forests.
These graphs show the first results for recharge.green from IIASA’s BeWhere and G4M models, optimizing the location of bioenergy plants to maximize either carbon sequestration (top) or bioenergy production (bottom). The gradiant of green colors shows the amount of carbon storage over the landscape, while the red boxes (and according gradient in red) show the harvesting intensity in different harvesting areas.
“Managing forests optimally for bioenergy requires more intensive management,” says Kraxner. That means shorter rotations where trees are cut more often. Such a forest is made up of smaller trees that may look more like “close-to-nature plantations” than an old-growth forest. In contrast, managing forests for carbon storage means letting the trees grow older, also good for biodiversity and environmental preservation.
In their analysis, Kraxner and the team compared two management strategies: restricting bioenergy production to a small land area, and managing it intensively, or spreading bioenergy over a large land area but managing less intensively over the whole area. They found that the same amount of bioenergy could be produced by managing a small amount of land area intensively for bioenergy production. This more intensive management on a small area of land would free up a larger land area for preservation and protection or other special dedication to ecosystem services.
“Both methods are sustainable,” says Kraxner, “but the optics are different. Intensification can be a good solution to provide renewable energy and at the same time preserve biodiversity and the more intangible values of mature forests.”
What do you think? What should our priorities be in managing Alpine forests?
Oct 2, 2013 | Alumni, Energy & Climate, Science and Policy
By Anthony Patt, ETH Zurich and IIASA (From ETH-Klimablog)
The first of three working group reports of the Intergovernmental Panel on Climate Change (IPCC) was made public last Friday. Previous reports served as guidepost for climate policy development. And yet some policies were clearly more effective than others.
Over the next several months, the IPCC will release a series of three volumes, one from each of its three working groups, together constituting its Fifth Assessment Report (AR5). The Working Group (WG) 1 report, on the science of climate change, was just published, while reports from WGs 2 and 3, covering climate impacts and adaptation, and the challenge of reducing or stopping climate change, respectively, appear in March and April of 2014.
Established by the United Nations in 1988, the role of the IPCC is to assess the state of the science, communicating it in a manner that is useful to policy-makers. Three of the previous four assessment reports have come at critical times in climate policy development. The first two supported negotiations of the current global treaty and its first major revision. The Nobel Peace Prize winning Fourth Assessment Report (AR4) was released in 2007, intended to guide the negotiations to the successor to Kyoto.
The AR4 delivered a convincing two part message: that to avoid dangerous climate change the world must embark on a pathway completely eliminating greenhouse gas emissions from industry and land use change by the second half of this century, and that such a pathway is both technically and economically feasible. Many expected this message to lead to a successful negotiation process to be completed in Copenhagen in 2009.
International climate negotiations have made little progress, but the IPCC still has value, argues Patt.
But negotiators failed to reach an agreement in Copenhagen, and have made remarkably little progress in the four years since. Moreover, both the recently published AR5 WG1 report and early drafts of the WG2 report on climate impacts and adaptation suggest that their findings will strengthen those from AR4, but will not add anything dramatically new. Some say that the IPCC is no longer of any value. I disagree, for two reasons.
First, the most ambitious policy developments are now happening at the national level, with countries like Germany, Switzerland, and even the United States planning exactly the kind of transition away from fossil fuels and high emissions pathways that the AR4 suggested was both necessary and possible.1 There is reason to believe that the actions of this smaller number of countries will deliver the technological progress to make a global transition possible. Without the AR4, it is easy to imagine such countries having behaved differently, while the AR5 WGs 1 and 2 reports ought to provide added justification.
Second, deep differences of opinion have emerged concerning the best policies to achieve national decarbonization goals. Ten years ago, almost all analysts were convinced that carbon markets, i.e. trading in CO2 emissions certificates, represented the ideal policy instrument. But these have worked poorly, while portfolios of other instruments, including subsidies and regulations, have exceeded expectations. Researchers have studied these outcomes.e.g. 2 They have found, for example, that the more successful policy instruments are those that work to minimize the risks that investors in new technologies face.
The AR5 makes clear that an energy system transition remains necessary, and indeed now appears even more urgent than it did a few years ago. It is now possible for the IPCC, in its WG3 report, to provide a critical appraisal of alternative strategies. This is badly needed.
This post was originally published on the ETH Zurich Klimablog (in German).
1. Lilliestam, J. et al. An alternative to a global climate deal may be unfolding before our eyes. Clim. Dev. 4, 1–4 (2012).
2. Peters, M., Schneider, M., Griesshaber, T. & Hoffmann, V. H. The impact of technology-push and demand-pull policies on technical change – Does the locus of policies matter? Res. Policy 41, 1296–1308 (2012).
About the author
Anthony Patt is Professor at ETH Zurich, and a Guest Research Scholar in IIASA’s Program on Risk, Policy and Vulnerability, where he serves as head of the Decisions and Governance Research Group. His research is on the effectiveness of policies at addressing risks and uncertainties in the area of climate change, considering both the restructuring of energy systems and adapting to climate impacts and vulnerabilities. Read more>>
Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.
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