The Great Global Experiment

Last night was all about climate change and its consequences. We had Kevin Anderson as a guest lecturer in our CEMUS course. He is the new holder of the Zennström Visiting Professorship in Climate Change Leadership here in Uppsala. This professorship is funded by UU alumnus Niklas Zennström and his organization Zennström Philanthropies. Apart from the visiting professorship he currently holds, Kevin is a professor of Energy and Climate Change at Manchester University as well as Deputy Director Tyndall Centre for Climate Change Research.

Kevin started off his lecture with some general information and “basics” about the weather and climate, which I was very grateful for. Of course, there are many factors which drive the weather and climate of our planet, such as gravity, topography or volcanic activity.  But it’s not only geological factors rather than life itself as well. That can be plants, animals or you and me. Nowadays the terms Greenhouse Effect (GE) and climate change tend to have a negative connotation and they are likely to be confused a lot. But we should recall that they are natural and partially even necessary in the first instance. Remember that without the GE we would all (literally) catch our death out there at an average temperature of -18°C. While it is uncontested that GE and climate change are real, the existence of anthropogenic climate change is still contested by some, even though there is evidence like the tight correlation between the increase in atmospheric CO2 concentration and anthropogenic emissions, or the declining ratio of carbon 14 in the atmosphere, suggesting that anthropogenic climate change is actually real.

Why the math does not suffice

Some of the big issues no one really expected some decades ago are positive feedback effects. Formerly, it had been calculated that doubling the CO2 concentration in the atmosphere to pre-industrial levels would lead to some 1°C rise in average temperature. Today we know that it will actually rather cause a 3°C change due to positive feedback effects. One example for this is the sea. Since polar ice is white, it reflects much of the solar radiation. When this ice melts due to global warming, the bright area decreases and the dark surface of the sea increases. This in turn leads to an even higher absorbance of heat and thereby more global warming. It is a vicious circle.

Global Warming Potential

Some of the drivers for climate change – and probably THE driver for anthropogenic climate change – are greenhouse gases (GHGs). There are many GHGs resulting from different sources (like water vapor, carbon dioxide, methane, etc.), so one is trying to make them comparable by looking at their global warming potential (GWP). That is how much a GHG warms the atmosphere within a certain period of time. If you are checking these numbers, the trick here is to look at the underlying time horizons very carefully. As the GWP is measured relative to CO2 and the gases have different lifetimes, the warming potential can vary a lot when using different time periods.

How to react to climate change?

If anthropogenic or not, climate change is real and already demands strategies today. There are generally two ways to tackle this issue: mitigation (= preventing CC) or adaptation (= adapt to CC). According to Kevin, not much – and definitely not enough – is happening in mitigating climate change today. At the moment we are focusing more on adaptation strategies. This has become necessary at the moment as a result of more extreme weather events, which lead to floods, food shortage, etc. In the medium to long term climate change will be likely to cause huge migration flows, increased military tension and other problems as well.

Why focus on 2°C goal?

A temperature rise by 2°C was formerly estimated to be on the border between acceptable and dangerous warming. Today it seems more likely that 2 degrees are way within the dangerous warming zone. We know that the impacts will be worse than anticipated, but today we have already reached an increase in temperature by 1 degree. Last year’s Paris agreement was an important step into the right direction because almost every single country agreed in written form to keep global warming well below 2°C above pre-industrial levels. Yet, this text is far from enough to save our planet. It doesn’t include any references to fossil fuels or decarbonization, it exempts aviation and shipping, it relies on negative emission technologies, and so on. So this agreement doesn’t provide a solution, but it provides some leverage for everyone engaging in climate change mitigation.

Possible scenarios

Pursuing the lecture, there are two possible future scenarios. The first one is that we start mitigation right now, as the only thing that’s missing is the will to act. This might enable us to actually stick to the goal of a 2°C warming. The second scenario will unstoppably occur if we do not react and will include temperature increases of up to 3-4°C. Under these conditions, summer heat waves in Europe for example will most likely melt roads, train tracks and kill thousands of people.


Some comments

This was surely one of the greatest lectures we had in the CEMUS course so far. It provided a nice density of information about climate processes and scientific basics, combined with a very inspiring discussion of the relevance of climate change and its possible future impacts. For my part I have learnt a lot yesterday. Many thanks to Kevin Anderson for visiting us!

I hope you guys felt like this was interesting. You probably knew a lot of it already (I knew at least sooome of it), but the lecture gave me some hope with respect to what is actually possible technologically and it also provided some new things to think about, like the sense or absurdity of negative emission technologies.

Sorry also that I didn’t manage to finish this last night. At least now I can almost wish you a good weekend!




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