Some Good News and Some Bad News

The second synthesis of the scientific literature (IPCC, 1996) concluded that, "On the whole, these studies support the evidence presented in the first intergovernmental panel on climate change (IPCC) assessment that global agricultural production can be maintained relative to baseline production in the face of climate changes likely to occur over the next century (i.e. in the range of 1-4.5 degrees celcius) but that regional effects will vary widely." (IPCC, 1996, p. 23). A more recent IPCC assessment (IPCC, 2001) goes further and asserts that "Most global and regional economic studies - with and without climate change - indicate that the downward trend in real commodity prices in the 20th century is likely to continue into the 21st century, although confidence in these predictions decreases further into the future." (IPCC, 2001, p. 237).

The good news is that scientists and economic experts participating in the IPCC assessments appear confident that global agricultural production can be maintained in the face of climate change. The bad news includes the facts that there is considerable uncertainty in the climate projections themselves; that assumptions have been made about the likely success of adaptation on the basis of very little research, and that the prospect of relative success at the global level even if fully justified, probably masks considerable regional variation in impacts and adaptive response capacity. In short there will be winners and losers.

Research by Parry and others (Parry et al., 1999) has concluded that the adverse effects of climate change on agricultural production are likely to be felt more in the lower latitude countries even though the amount of temperature change there is projected to be less than in higher latitudes. Some of this higher vulnerability may be ascribed to environmental conditions where crops are grown close to their limits of heat tolerance or moisture availability. Mostly it is supposed to reflect a lower adaptive capacity in socio-economic systems.

In reaching their positive conclusions about the future of world agriculture the IPCC authors note that agriculture is subject to a wide range of multiple stresses and impacts and that climate change is just one factor among many that the sector has routinely to contend with. Among these factors climate change is often considered to be a relatively minor, or a distant threat. The high degree of confidence reported about global agriculture probably stems also from the commonly accepted view that farmers and the agricultural sector have, up to now, demonstrated remarkable resilience in the face of all kinds of change, and that sufficient adaptive capacity to cope with climate and other risks has been demonstrated in the past and will continue. But adaptive capacity is not equally distributed. And the climate changes threaten to be of an unprecedented magnitude and are likely to occur at a rate not previously experienced in human history.

At the same time it is recognized that the uncertainty associated with the threat of climate change is less than the uncertainty which surrounds changes in technology; in competitive markets and trade regulations; changes in relative efficiency and comparative advantage, and consumer demand. In the climate community it is commonly asserted that agriculture is one of the sectors most vulnerable to climate change. Perhaps it would be more accurate to say that in the face of the great uncertainties that agriculture faces from changes in technology, economic and social forces, we have little or no understanding of what the added stress of climate change will do.

The output from global climate models (GCMs) is not only uncertain (a wide range of temperature increases is projected), but is also on a coarse scale and is commonly expressed in terms of changes in mean temperature and precipitation. Thus the scale and the variables are not those most relevant to choices in the agricultural sector. To make informed decisions farmers require information on short-term seasonal and inter-annual variability for very specific localities. This circumstance contributes to a general sense that long-term climate change is not, and should not be high on the farming agenda.

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