Improving the habitability of Africa

[Mirannan]

I'd like to start a discussion about the possibility of, and methods for, improving the habitability of Africa - large parts of which are too difficult to grow crops in, and also large parts of which are distinctly unhealthy. (Tsetse flies and mosquitoes being just two of the reasons for the latter.)

Probably the largest part of Africa with problems is the Sahara Desert. One project, or set of projects, I've seen discussed is the digging of sea-level canals connecting the sea (usually the Mediterranean) with below sea level areas of desert such as the Qatarra (sp?) Depression. Which would probably increase rainfall drastically in the areas around these new seas. I believe (can't confirm; can't find a large-scale topographic map) that a fair proportion of Chad is very low-lying, too.

Any thoughts?

 

[WaylanderToo]

IIRC the Sahara is growing the problem as I (a non-sciencey person) see it is that this would be a generations long project and while the payoff would be immense in 50/100 years time it'd be too expensive for most companies (and governments) to risk on such a long term venture. Can it be done? I suspect that the answer is most certainly 'yes' as the Israelis have done similar (on a far smaller scale) in some of their desert

 

[SilentRoamer]

The problem is that you can't just increase the water content in the Sahara or large swathes of sub Saharan Africa without having an impact on the global systems of the world.

The Saharan desert drives much of the worlds weather patterns and has a huge impact on global weather and animal migration routes.

Fundamentally any changes in large parts of the earths weather patterns are going to have other effects - especially on biodiversity. It could cause extinction of animals as their natural habitat is eroded.

The Sahara and large strips of the Middle East are expected to get hotter and hotter over the coming years and there are predictions that eventually it could become uninhabitable: Middle East Summers Could Become Unlivable By End Of Century

Apart from being unfeasible I don't think we could even appreciate all of the consequences.

 

[chrispenycate]

I wrote a series of short stories about dedesertification (hot desert) some years ago, (forest, polytunnel, black plastic rubbish, mountain) in which, for a few hundred million dollars and with political stability (doesn't require a 'nice' government, just an established one with no major uprisings or wars) could improve crop yields massively. Lots of goats would have to go, which means lots of poor tribes would have to suffer, and calculating the interaction between that and the rest of climate change is beyond me and, I suspect, all the model-making predictive meteorologists, but it almost has to be overall positive.

As regards habitat - the Sahara, in particular, is recent desert. Unlike the Kalahari, very few species have really adapted to it. And the change would be gradual, giving scorpions and things time to find conditions that suit them. (rather than building a dam and flooding out thousands of square kilometres).

 

[Ray McCarthy]

the Sahara, in particular, is recent desert.

Goats.
Almost all desertification in Africa and Middle East has more than doubled in last 2,000 years due to grazing. Goats are worst, as they will pull up and eat the roots.

 

[SilentRoamer]

As regards habitat - the Sahara, in particular, is recent desert. Unlike the Kalahari, very few species have really adapted to it. And the change would be gradual, giving scorpions and things time to find conditions that suit them. (rather than building a dam and flooding out thousands of square kilometres).

Anything along human timescales is not gradual - even adapting a region over 2,000 years would likely still cause mass extinction in those desert species because evolutionary timescales are an order of magnitude above human timeframes.

Even if you were to assume that the scorpions et. al. managed to find another ecological niche there is no guarantee this niche would not already be filled and then cause animal displacement.

Ultimately I think transforming any region in any remotely human timescale will cause problems for species that have evolved into niches over millions of years.

 

[Mirannan]

The problem is that you can't just increase the water content in the Sahara or large swathes of sub Saharan Africa without having an impact on the global systems of the world.

The Saharan desert drives much of the worlds weather patterns and has a huge impact on global weather and animal migration routes.

Fundamentally any changes in large parts of the earths weather patterns are going to have other effects - especially on biodiversity. It could cause extinction of animals as their natural habitat is eroded.

The Sahara and large strips of the Middle East are expected to get hotter and hotter over the coming years and there are predictions that eventually it could become uninhabitable: Middle East Summers Could Become Unlivable By End Of Century

Apart from being unfeasible I don't think we could even appreciate all of the consequences.

Interesting. I've seen reports stating that the ME and Sahara aren't going to be the first no-go zones, because even very high temperatures are survivable as long as the humidity is low. (I've been in 115 deg F heat and been fairly comfortable, because it was in the middle of the High Veldt of South Africa which has a climate rather like Nevada for those who don't know.) One does of course need a good supply of water.

The real killer is moist heat. The reports I've seen indicate that a wet-bulb temperature of about 35 C is fatal, and fairly quickly at that; the human body can't get rid of heat in conditions like that. This corresponds to a rise of maybe 3-4 degrees in some tropical rainforest zones, which are of course very humid much of the time.

Yes, fatal. As in; go outside for more than a few minutes and you die of heatstroke. This would of course cause an ecological catastrophe, because any warm-blooded animal also has limits - although admittedly rainforest animals are adapted to hot and humid conditions and their limits are probably higher.

 

[Ray McCarthy]

The real killer is moist heat

Yes.
I was in 44 C in a near desert area, fine as long as you drink and wear a hat.
Even 30C is ghastly here on the very few occasions we had it (80% RH!).
I found Ohio in end August horrible in afternoon when I was working there for a few weeks.

 

[SilentRoamer]

Mirannan if you are interested this is an interesting article:

Climate extremes: The worst heat waves to come : Nature Climate Change

Sorry for the referral link, the only way to get the full Nature article is to use a referral link as it is behind a pesky Nature paywall. If you happen to have a Nature sub then the original link is:

Climate extremes: The worst heat waves to come : Nature Climate Change

 

[Stephen Palmer]

There's always the Green Wall of Africa...

 

[WaylanderToo]

mind you here is the interesting part... there is actually a LOT of water under the Sahara

 

[Parson]

Interesting..... Could global warming and the corresponding water level rise be mitigated to a point by digging those canals to the Sarah?

 

[Mirannan]

Interesting..... Could global warming and the corresponding water level rise be mitigated to a point by digging those canals to the Sarah?

Possibly, IMHO. Reason? Well, one of the controlling factors of global temperature is the albedo of the Earth. And clouds have a much higher albedo (reflect more light back into space) than does Saharan dirt. And large areas of open water in the middle of the Sahara are likely to increase cloud cover.

Complicated, isn't it? (Which is one rather good argument against warmists, imho.)

On the subject of CO2 and global warming; actually, it matters what's making the CO2 and where. A good example of this is the issue of jet travel, thought of as an invention of Satan by AGW believers. It turns out that the effect of jet travel on average temperatures might well be neutral or even negative, because jet travel increases cloud cover. The reason for that can occasionally be seen; jet contrails sometimes spread out into fairly extensive high-level cloud cover.

I've seen that myself; I live maybe 30 miles from Manchester Airport, and every so often we have a day which would be completely clear if it wasn't for the spread-out contrails covering half the sky.

 

[anno]

Why are we discussing changing the birthplace of all humanity,the most diverse set of habitats and the most biodiverse continent on the planet?

Humans,you kill me...

 

[Mirannan]

Why are we discussing changing the birthplace of all humanity,the most diverse set of habitats and the most biodiverse continent on the planet?

Humans,you kill me...

One reason is that we already have. Goat herding has caused the Sahara to expand south by hundreds of miles - and that problem is still ongoing.

 

[Wrenn Flint]

Interesting. I've seen reports stating that the ME and Sahara aren't going to be the first no-go zones, because even very high temperatures are survivable as long as the humidity is low. (I've been in 115 deg F heat and been fairly comfortable, because it was in the middle of the High Veldt of South Africa which has a climate rather like Nevada for those who don't know.) One does of course need a good supply of water.

The real killer is moist heat. The reports I've seen indicate that a wet-bulb temperature of about 35 C is fatal, and fairly quickly at that; the human body can't get rid of heat in conditions like that. This corresponds to a rise of maybe 3-4 degrees in some tropical rainforest zones, which are of course very humid much of the time.

Yes, fatal. As in; go outside for more than a few minutes and you die of heatstroke. This would of course cause an ecological catastrophe, because any warm-blooded animal also has limits - although admittedly rainforest animals are adapted to hot and humid conditions and their limits are probably higher.

Truth. I live in Mississippi where the temps get over 100 F and the humidity is awful. Your sweat doesn't evaporate, so your body can't cool itself. I keep towels in a cooler of ice water when I'm working outdoors in the summer.