What has climate change done to the seasons?

July 7, 2009

     By Duncan Green     

Yesterday, Oxfam published Suffering the Science, a powerful synthesis of the science and the human havoc that climate change is already wreaking. The thing that caught my eye was ‘What Happened to the Seasons?’, an input paper by my colleagues Steve Jennings and John Magrath bringing together evidence from 15 countries on how seasons are changing and the impact on poor people. Sounds techie, I know, but I found it gripping – here’s some excerpts.

Summary of climatic observations: the following observations are reported consistently across all our studies:

1. The seasons appear to have shrunk in number and variety, in that what could be termed relatively temperate “transitional” seasons are truncated or have disappeared altogether. People’s perceptions are that they are progressively being replaced by a more simplified pattern of seasons whose characteristics are predominantly hot (hotter) and dry or hot (hotter) and wet.

2. Increased temperatures overall, particularly in winters.

3. Rain is more erratic, coming at unexpected times in and out of season. In particular there is less predictability as to the start of rainy seasons. Generally rainy seasons are shorter. In mountainous areas there is considerably less snowfall. Dry periods have increased in length and drought is more common.

4. Within recognisable seasons unusual and “unseasonable” events are occurring more frequently, such as heavy rains in dry seasons, dry spells in rainy seasons, storms at unusual times, dense and lingering fogs and temperature fluctuations.

5. When rains do come they are felt to be more violent and intense and punctuated by longer dry spells within the rainy seasons. Dry spells and heavier rain increase the risk of flooding and crop loss.

6. Winds – and storms – have increased in strength. They may come at unusual times. Prevalent wind directions have also shifted.

Summary of human impacts: The precise effects are very geo-specific, but broad patterns seem to hold true generally:

1. Unpredictable weather has always presented serious problems for smallholder farmers and fishing communities in poor countries, but farming is becoming even more difficult and risky because of the greater unpredictability in seasonal rainfall patterns. Heat stress, lack of water at crucial times and pests and diseases are serious problems that climate change appears to be exacerbating. These all interact with ongoing pressures on land, soils and water resources that would exist regardless of climate change. The most common observation is that the changes are “shortening” the growing season.

2. Unpredictability requires greater investment of time, energy and resources in order to seize the right moments and to maintain crops (and animals) through dry spells.

3. Rising temperatures and unpredictability together can be an incentive to diversification – whether desired or as a matter of necessity. But the ability to diversify is highly dependent on many factors and generally requires support to succeed.

4. Seasonality difficulties are strengthening trends within rural societies for people to move out of agriculture to a greater or lesser degree and to move to urban areas. Men and women respond differently, although exactly how depends very much on each society.

5. Seasonality difficulties are likely to increase inequalities between those who are in a position to diversify – including taking advantage of the ability to grow new crops – and those who are not.

6. Women are particularly badly affected by the combination of climatic and environmental stresses, but their particular needs and wishes for adaptation are less likely to be heard or acted upon.

Effects on psychology and culture: Changes in the seasons create existential shocks, to individuals and to societies by threatening belief systems, cultural practices and, as a result, social relationships. Bewilderment, disorientation and a sense of loss are often palpable in interviews, along with sadness and fears for the future.

Carlos Ling, an Oxfam Project Officer in the Atlantic coast area of Nicaragua, says that the elders among the Miskito Indian communities “are baffled by the changes. … The crop season has been moving from the traditional dates and this is very, very important because such climate change affects your understanding of the whole Universe, not just your way of living. For people it’s very important to understand that on a particular date you plant the seeds in the ground and it is magical, it involves a lot of energy and also hope for the future, and also certainty of a new crop. When certainties move you feel a loss of control of your life, which is demoralising. … Even if you had no control of your health or your education because of poverty or racism, you had that certainty inside you. Now there’s nothing to stand upon; climate change has had that kind of impact”. It also means that the elders have lost respect in the eyes of the younger generation.

Do these perceptions fit the meteorological data? There’s a fascinating digression on the differences between how farmers and meteorologists measure the weather (I may come back to that in another blog), but the paper concludes:

‘These perceptions of changing timing and character of seasons seem often to find support in the meteorological record and are also to some degree consistent with climate model simulations.’

What I love about ‘What Happened to the Seasons’ is the way it combines genuine respect for both the science and the perceptions of poor people (with dozens of vivid quotes from communities living the consequences of climate change). Where there are disparities between the two, it makes real and intelligent efforts to understand them. Bravo.

July 7, 2009
Duncan Green