Climate Change, Variability, and Darfur

A couple of things that crossed my virtual desktop recently highlight the difficulty of thinking well about the impacts of and responses to climate change and climate variability. The first is a story by Scott Baldauf from the Christian Science Monitor this morning: Is Darfur the first climate-change conflict? The second is a paper by Richard Washington and colleagues in the latest Bulletin of the American Meteorological Society.

Baldauf’s theme is the possibility of a link between climate change and crisis in Africa:

As delegates gather Monday in Kenya for a United Nations conference to set new targets to reduce fossil-fuel emissions after 2012, climate change is a present reality for many Africans.

In Kenya, Sudan, Ethiopia, Somalia, and Chad, people are already seeing the repercussions – including war. The conflict between herders and farmers in Sudan’s Darfur region, where farm and grazing lands are being lost to desert, may be a harbinger of the future conflicts.

But what sort of a “change” are we talking about here? Are we talking about the sort of permanent nonstationarity implied by greenhouse-induced climate change? That’s the clear implication of Baldauf’s piece:

[C]limate change is already hurting people here in Africa, according to a report issued last month by a coalition of British aid groups. The number of food emergencies encountered each year in Africa have tripled since the mid-1980s, the report says. This year alone, more than 25 million Africans faced a food crisis.

Even though temperatures in Africa have only warmed by an average of 0.5 degree C. over the past 100 years, desert lands are advancing into once arable rain-fed areas, and wetter equatorial parts of Africa are getting wetter, often leading to devastating floods.

But there is an obvious unstated confusion here. What do we mean by “change”? Baldauf clearly seems to be implying the classic media/public discourse definition – “climate change” = “anthropogenic change.” This is where the Washington paper offers some extremely useful clarification:

In what way can the benefits resulting from management of the effects of climate variability be bridged with preparations for the longer time-scale impacts associated with climate change? Here we need to ask the question of what defines the time scales of variability and change. Unless formal distinctions between climate change and climate variability are drawn, climate change itself becomes a difficult concept to define, because all natural “change” is merely a reflection of variability on some appropriate time scale. The United Nations Framework Convention on Climate Change (UNFCCC) addresses this problem by defining climate change only as that component induced by anthropogenic activities. Thus, in the strictest sense, all activities under the UNFCCC banner address only the anthropogenic component, and provide no support for activities related to natural variability on whatever time scale. The terms of reference of the Intergovernmental Panel on Climate Change (IPCC), on the other hand, require consideration of both natural and human-induced variability and change. Nevertheless, the IPCC has tended to focus its activities on clearly discernable anthropogenic influences on climate, be it significant changes attributable to human influence or signals apparent in projections some decades into the future.

Washington et al. note that the early signs of anthropogenic change are in evidence in Africa. But the actual steps being taken on the ground now in Africa relate to variability, not long-term anthropogenic trends:

There is good reason for this, because it recognized by some that the ability to handle current climate variability is a vital and prime, if not a sufficient, requirement for managing a future changed climate; handling current climate variability further is directly achievable and provides immediate production and capacity benefits. Adaptation, however, on whatever time scale, is frequently endogenous (spontaneously occurring within a society rather than managed by an external organization or institution), and endogenous adaptation will inevitably form much of the response to both climate variability and to anthropogenically induced change. The excess adaptation required to cope with climate change, beyond that which will be supplied through dealing with the ongoing effects of climate variability, will also need to be handled in a managed manner, but we stress that the immediate imperative is to address climate variability in its present form as part of the continuum of change….

Which is as it should be.