So What Exactly Is ‘Extremely Dangerous’ Climate Change?

Before we get a handle on  ‘extremely dangerous’ climate change, let us start by getting an understanding of what everyday ‘dangerous climate change’ means. In the opening paragraph of the introduction to the IPCC Fourth Assessment Report we get a little enlightenment (see here):

The ultimate objective of the United Nations Framework Convention on Climate Change (UNFCCC) is to achieve the stabilization of greenhouse gas (GHG) concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

And in the Copenhagen Accord of December 2009 we see this:

We underline that climate change is one of the greatest challenges of our time. We emphasise our strong political will to urgently combat climate change in accordance with the principle of common but differentiated responsibilities and respective capabilities. To achieve the ultimate objective of the Convention to stabilize greenhouse gas concentration in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system, we shall, recognizing the scientific view that the increase in global temperature should be below 2 degrees Celsius, on the basis of equity and in the context of sustainable development, enhance our long-term cooperative action to combat climate change.

Thus we could define ‘dangerous climate change’ as something that threatens food production and economic development, and this in turn is expected to take place at two degrees of warming above pre-industrial temperatures. Note that we are now straying out of the life sciences and into the social sciences. Further, the direction of causation has gone from CO2 emissions, to atmospheric CO2 concentrations, to global mean temperatures, to socio-economics and geo-politics. The final step of this progression is something most scientists are loathe to make. As Gwynne Dyer writes in his book “Climate Wars”

….the modellers….wisely stay well clear of any attempt to describe the political, demographic and strategic impacts of the changes they foresee.

And this is why the IPCC’S famous ‘burning embers’ diagram (referred to in my last post here) uses wording that carefully avoids encroaching on the area of economics or geopolitics in any discernible way.

Nonetheless, we have a tentative grasp on the societal impacts of dangerous climate change from the IPCC (somewhat loosely defined as economic and agricultural disruptions), so let us see how far up the causation change the scientists can take us with respect to ‘extremely dangerous’ climate change.

Scientists like Kevin Anderson at the Tyndall Institute believe that even at two degrees Celsius of warming we are  in danger of seeing ‘extremely dangerous’ climate change and given the fact that we could overshoot to four degrees and beyond, the ‘extremely dangerous’ outcome appears almost inevitable.

To better understand what a world subject to such ‘extremely dangerous’ temperatures would actually look like, a conference entitled ‘4 Degrees and Beyond’ held was in Oxford in September 2009 (conference proceedings can be found here), and subsequently a series of academic papers were authored following the conference and were published in The Royal Society’s Philosophical Transactions in January 2011 (the papers can be found here). Together, this research provides a detailed list of impacts at both the sectoral and geographical level. If you want to get a feeling for the kinds or risks you and your family face, then I strongly recommended you follow the links above. But what you won’t get is any higher level macro economic, or geopolitical analysis.

While most scientists are wary of pushing past the scientific impacts and entering into the realm of geopolitics, Kevin Anderson is one of the few who does. Here is his view of what a four degree Celsius and rising world will look like:

For humanity it’s a matter of life or death. We will not make all human beings extinct as a few people with the right sort of resources may put themselves in the right parts of the world and survive. But I think it’s extremely unlikely that we wouldn’t have mass death at 4C. If you have got a population of nine billion by 2050 and you hit 4C, 5C or 6C, you might have half a billion people surviving.

At last something pretty concrete. It may or may not be true, but that is the whole point of doing a risk assessment. In other words, we need to ask the question “What is the probability associated with a tail risk of three or four degrees of warming around within our or our children’s life times, and if this came about what would be the consequences?”

While Anderson is one of the few scientists who have a view on record that stresses the potential for geo-political chaos, the military are much more forthcoming. either in publications that originate in departments of defence or military associated think tanks. Most such publications present a shopping list of potential climate change outcomes or present one central scenario that is the best estimate case. Occasionally, however, you do see a scenario-type approach, and the Age of Consequences report put out in 2007 by the US Center for Strategic & International Studies is one such example. The report outlines three scenarios: first, a 1.3 degree Celsius rise in temperature by 2040 which is called the expected scenario; second, a so called severe scenario of 2.6 degrees of warming by 2040; and, third, a catastrophic scenario of 5.6 degrees of warming by 2100. Given our risk time horizon, let’s see what the ‘severe’ scenario has in store for us:

In the case of severe climate change, corresponding to an average increase in global temperature of 2.6°C by 2040, massive non- linear events in the global environment give rise to massive nonlinear societal events. In this scenario …. nations around the world will be overwhelmed by the scale of change and pernicious challenges, such as pandemic disease. The internal cohesion of nations will be under great stress, including in the United States, both as a result of a dramatic rise in migration and changes in agricultural patterns and water availability. The flooding of coastal communities around the world, especially in the Netherlands, the United States, South Asia, and China, has the potential to challenge regional and even national identities. Armed conflict between nations over resources, such as the Nile and its tributaries, is likely and nuclear war is possible. The social consequences range from increased religious fervor to outright chaos. In this scenario, climate change provokes a permanent shift in the relationship of humankind to nature.

From the above, we can get a tentative feel as to how bad things could get. So, as a working definition, I propose that ‘extremely dangerous’ climate change be taken to mean a transformation of the natural environment that starts to re-arrange societies in a non-linear manner. Further, such a rearrangement will have negative implications for the wealth and health of individuals and families in not only developing countries but also developed countries.

So given the complexity of the issue, how can an individual assess this climate change risk?

Well, the world is a complex place and we already have to make decisions in the face of uncertainty and incomplete information, so what else is new? Actually, in comparison, say, with the decision to marry, I think it is far easier to assess the risk of global warming. For a start, we have a number of facts that can move us quite far up the causation curve  as we move from carbon emissions, to atmospheric C02 concentrations, to global mean temperatures—and then finally to the much more difficult-to assess socio-economic and geopolitical consequences. So as more data comes in, we will have a progressively better idea of how hot things will get. We will then have to take a stab at the economics and politics; but if you have ever been involved in the financial markets, you will have had to do that every day regardless.

In sum, climate change is tough, but so is an assessment of the future risk and return when buying 10,000 dollars worth of shares in Apple Computer or Google. Further, climate change is a high stakes game from a risk perspective: if the value of your holdings in Google crashes, it may be painful for your wealth. If climate change comes in at the negative end of the distribution, it threatens countless lives—maybe including you and your family’s. That is why I think it deserves attention from any thinking person who considers the future.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s