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The World Four Degrees Warmer: A New Analysis from the World Bank

By: Dr. Ricky Rood, 5:00 AM GMT on November 19, 2012

The World Four Degrees Warmer: A New Analysis from the World Bank

I ended my last article with the idea that our motivation to address climate change would likely be a series of climate disasters. Each hit will be a blow, and each blow will cause us to accumulate a bit more climate fatigue.

Back in 2011 I changed my class, and I started to teach that we needed to prepare for a world four degrees Celsius warmer. I felt that describing that warm world and developing adaptation strategies would make the climate change problem more concrete. It would make the costs more real and bring the problem home to cities, communities, and people. It would motivate technology, solutions. Ultimately, I feel it will motivate us to take the reduction of greenhouse gases more seriously.

Originally, much of my material was taken from a special issue of The Philosophical Transactions of the Royal Society. In the Introduction by Mark New and colleagues, they argue that the projected rate of population growth and our current warming trajectory work to maximize stress at the same time. With warming approaching four degrees, stress on resources and human systems related to climate change become comparable to those from population stress.

Today a new report from the World Bank gives an analysis of the world four degrees warmer and comes to the conclusion that “a 4 degree Celsius warmer world must be avoided.” (PDF of Report). If the average increase of the global surface temperature is 4 degrees, then the regional changes will be much higher. In the analysis by the World Bank, they point out that the geographical size of regions of extreme heat and drought has increased and will increase significantly. This change in area is in concert with increased frequency of occurrence. The regional changes in the summer in the continental United States will be of order six degrees Celsius, say ten degrees Fahrenheit. Think about the last two summers in the United States, and add ten degrees.

The World Bank is worried about development and poverty. They spend much of the report analyzing the intersection of climate change, climate stress, population, and population stress. For example, water stress related to both precipitation and increasing temperature occurs in regions of increasing population, where stress is already high. This brings attention that this is a problem of population and climate change, not one or the other. The report talks about the compounded effects of drought, flood, extreme weather, people, and vulnerability. The report states, “A 4°C world is likely to be one in which communities, cities and countries would experience severe disruptions, damage, and dislocation, with many of these risks spread unequally. It is likely that the poor will suffer most and the global community could become more fractured, and unequal than today.” Each hit will be a blow, and each blow will cause us to accumulate a bit more climate fatigue.

And in the language of development bankers and economists: “Projections of damage costs for climate change impacts typically assess the costs of local damages, including infrastructure, and do not provide an adequate consideration of cascade effects (for example, value-added chains and supply networks) at national and regional scales. However, in an increasingly globalized world that experiences further specialization in production systems, and thus higher dependency on infrastructure to deliver produced goods, damages to infrastructure systems can lead to substantial indirect impacts. Seaports are an example of an initial point where a breakdown or substantial disruption in infrastructure facilities could trigger impacts that reach far beyond the particular location of the loss.”

The message of this report is that when considering the cost of a world four degrees warmer and the overlap of that warmer world with people, our built infrastructure, and fragile countries, then we must take the steps to avoid that warmer world. And, that is likely to be four degrees on the way to six degrees.

Next, I will consider this report in context of the International Energy Agency report North America leads shift in global energy balance, IEA says in latest World Energy Outlook.


New World Bank Report on a world four degrees warmer.

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The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.