Climate Change Projections for Africa

So the 26^th Region Conference for Africa is in session this week and one of the items on the agenda is improving food security in the face of recent climate trends. A report on the impact of climate change in Africa has been prepared which summarises the plight of the continent and discusses a number of options for fighting back. In this post I’ll deal purely with the climate change projections.

Africa has a long history of food crises but one of the main reasons why it is particularly vulnerable to climate change is that it is particularly reliant on rain-fed agriculture. Irrigation and water conservation are poor throughout Africa and changes to rainfall patterns due to Global Warming could have a significant impact on annual soil moisture levels.

The most vulnerable regions are the semi-arid countries around Sub-Saharan – where population growth is higher than any other region in the world – and also South Africa and some of its neighbouring countries. These regions are predicted to show reduced rainfall all year round, threatening a potential water crisis.

This has to some extent already begun. Over the last 40 years many of Africa’s major water courses have seen a 40-60% reduction in discharge. Lake Chad has been reduced from 20,000km² in the early 1960s to less than 2,000km in the early 21^st century. While this statistic may not be as bad as it appears – Lake Chad is a historically shallow lake – it still demonstrates that Africa is already on the path to disaster.

Further reductions in river discharge, due to decreases in rainfall, are likely to affect agriculture that depends on these rivers for irrigation. Agriculture along the Nile is particularly vulnerable.

Coastal and tropical regions, among others, are likely to experience slight increases in rainfall, but this is not necessarily a good thing for farmers either. The increase is likely to be seen during the winter months, with an extra 5 – 20% between December and February and a reduction of 5-10% between June and August. There is also likely to be greater variability between wet years and dry years. Combined, these trends mean that, while overall rainfall might increase, the number of droughts will also increase.

Finally, some coastal regions in countries such as Mozambique, Tanzania and Angola are at risk from rising seas, while coral reefs could also be destroyed by higher sea temperatures.

So the overall picture for Africa? Pretty bleak – especially considering that its population continues to rise and much of its existing farmland is slowly being degraded. I’ve already mentioned some of the implications for agriculture here, but the next post will focus on purely food production.

African Climate Change Report

A recent report on the impact of climate change in Africa has concluded that if temperatures continue to rise, Africa could be in trouble. No shit, Sherlock.

The report itself is intended as preliminary reading material for this week’s Regional Conference for Africa. It covers quite a broad range of material and some of it makes interesting reading. There are obligatory references to economics and production that often make my blood boil – climate change is NOT about reductions in GDP, it’s about the unnecessary degradation of the environment and the potential ecological and food crises that could result – but once you get beyond that there’s some interesting information there.

I’m going to read through it and try and summarise it over the next few blog posts.

Desertification and Population Pressure

My last post on climate change evidence concerned the doubt that still surrounds the issue of man-caused global warming. Personally, I can't see how we could possibly not have influenced the climate – we can’t even brush out teeth without damaging consequences.

That’s not necessarily an exaggeration, either. Desertification of farmland in semi-arid areas poses an increasingly ominous threat to the wellbeing of both our environment and the human race. UNEP reckon about 20 million hectares of land are lost to desertification each year. That’s around 200,000 km² or a little 1% of the world’s estimated arable land. It doesn’t take a genius to realize that isn’t going to leave us with much in around 100 years or so.

You might be tempted to think that this is a strictly developing world phenomenon, but you'd be wrong. In fact the most rapid desertification is happening in Australia, Spain and the USA. What’s causing it? Like I say: brushing your teeth.

Causes of Desertification

Okay, so it’s not quite that simple. Our ecosystem is both fragile and complex and any number of things can tip it out of balance. The main cause of desertification is poor soil conservation. The top layer of any soil is important and failing to maintain a healthy layer of humus is one of the prime reasons for the failure of arable land.

Crop rotation, composting and responsible use of fertilizer are all ways of getting the best out of soil but many farms practice intensive monoculture and use excessive chemical inputs to get the most out of the land. This inevitably leads to short term profit and long term soil degradation. Often such practices come about because of western business models that emphasis profit over responsibility. The gluttony of the developed world could well be contributing to the slow death of developing countries with marginal farmland.

Deforestation is another direct contributor. Reducing the concentration of trees affects the thermal properties of the land and often leads to reduced rainfall. Without an adequate water supply, the humus layer begins to degrade rather quickly and the soil begins to thin and die.

In developed countries with high urban densities and efficient water systems this same effect can be produced by excessive water consumption. Tapping into the aquifer and draining the water table can intensify the effects of dry periods and cause degradation on the surface. Excessive water demands from urbanization and tourism in countries such as Spain are putting large areas of farmland in danger – the UN reckons around 12% of Europe is in immediate danger of desertification and as much as 60% on the Iberian peninsula.

Which brings me back to brushing your teeth. You can use 12 gallons on water when you run a tap for 3 minutes - switching the tap off while you brush can save a lot of water over the year. There's a lot more you could be doing, too - taking shorter showers and showering more often than bathing, for example. But the toothbrushing fact is a nice clean tagline which media men (and me) like to seize upon. I guess it emphasises just how important some of our most banal actions are. Water conservation isn’t just a key issue in Sub-Saharan Africa; it’s an important principle that should apply to everybody and which needs to be taken seriously.

Feedback from Population Growth

It gets worse, too. Because of the impact of intensive farming and urbanization on the rate of desertification, the rate of damage theoretically increases as a population grows. The UN estimated the Earth’s population to be around 6.8 billion at the end of 2009 and the current rate of increase is around 100 million per year.

An optimistic blog post by Fat Knowledge estimates the ultimate carrying capacity of the Earth to be anything from 30 billion to 100 billion people – if all available farmland were used and everybody ate corn. But this estimation does nothing to take account of the effect that population growth will have on available farmland.

The agricultural capacity of the planet is already in decline and will continue to trend that way as the population grows. Sooner or later we’re not only going to be in a sticky situation; we'll have more people than the planet can support and our ability to support them is going to go into rapid decline. If Thomas Malthus is to be believed we'll probably keep on breeding past this point too, until something cataclysmic happens.

There are examples of this from history. History tells us that the pre-renaissance population crash in the UK was the result of the Black Death, but such a simplistic estimation fails to recognise that the population was already in steep decline before plague hit. The Black Death certainly helped, a large part of the near 3 million reduction in population was the result of crop failure.

I’m not going to try and translate that into a global context. The mesasge however if fairly clear; desertification is a very real threat and sooner or later the degradation of farmland coupled with excessive population growth is going to lead to a major and rather terrible global food crisis.

Not that I want to ruin your morning or anything.