Middle East & Africa: Climate

More so than any other region of the world, the climates of the Middle East and Africa play an important role in human settlement and development. First, we will look at the extreme nature of the climate in the Middle East and then we will examine the variation of climates in Africa. As you can see in this map, the dominant climate of the Middle East is desert. As you might imagine, the extremely arid, or dry weather, poses many challenges to human settlement. As we have already established, water plays a pivotal role in food production and therefore where humans live. One of the best examples of this is found in Egypt, near the Nile River delta, where irrigated agriculture is possible. However, due to the harsh conditions of the Sahara desert, very few people live beyond the banks of the Nile. While the climate of the Middle East is primarily desert, the extreme differences in Africa’s climate make its environment much more complex.

As you can see, the African climate consists of everything from the driest conditions, the deserts, to the wettest, the rainforests. You may remember from the climate discussion how high and low pressure zones create differing environments. Recall that low pressure is associated with rising air and therefore, cloud development and rainfall; whereas high pressure is associated with sinking air and thus dry conditions. As this image illustrates, due to the fact that Africa straddles the equator, it has a relatively symmetrical climate. At the equator, low pressure dominates and this area is designated as rain forest. However, at approximately 20-30 degrees north and south latitude, the area is desert. Remember, at this latitude, high pressure dominates, thus the very dry conditions. Then, in between these extreme zones, you find the savanna and steppe climates. These climate types receive a moderate amount of precipitation and therefore, the dominant vegetation type is grassland.

One of the most productive regions in Africa is called the Sahel. The Sahel is a drought-prone savanna region just south of the Sahara desert. As we prepare to see an image showing vegetation in Africa, look for the effect that climate belts have on vegetation. Once again, you see the effects of the dry conditions to the north and south and the rainforest near the equator. Now that we have established that the savanna and steppe climates are located between the desert and rainforest, let’s go one step farther to understand the processes that create this environment. During the summer, the low-pressure zone responsible for the rainforest climate and the high-pressure zones responsible for the deserts, move slightly to the north. As the low-pressure belt moves over the Sahel, it brings rainfall. However, during the winter, these belts move in tandem to the south. Therefore, the Sahel is now dominated by high pressure. The areas of steppe and savanna, just to the south of the equator, experience the same seasonal rainfall and drought as the Sahel, just at opposite times of the year.

Notice on this infrared image, the cloud cover, or the lack thereof, over Africa: the east-west belt of clouds, created by low pressure, causes rainfall near the equator. You can also identify the high-pressure zones, just to the north and to the south of the equator, by the lack of clouds. The extreme environmental conditions in Africa have contributed to the lack of food production, and therefore development, on that continent. In the next section, Monsoon Asia, you will see where more favorable conditions have contributed to better food production, and therefore in increased development..

Thoughts About Some Mind-Bending Earth Images

So, now that we’ve been regularly photographing the Earth from space for decades, we can watch in like time-lapse format, as our planet changes – usually, as we change our planet. Huge scale stuff. And Google has just released a tool that makes this easier. Basically, you can scan around the entire world and watch the last 25 years of life on Earth. What the world was like when I was four versus what the world is like now. So I wanted to share some of the cool things that I found while doing that. First, here’s my hometown of Missoula And if you look carefully, you can see some new neighborhoods being built and all the boxstores going into the edge of town. Bit of a small town but it has changed in the last 25 years. More interesting probably is the amazing sprawl of Orlando, where John, you and I grew up. But really, the most fascinating bits are where humans have had their deepest influences. America’s insatiable appetite for cheap coal power, our wonderful lifestyles has lead to a practice called mountain top removal mining, in much of Appalachia.

I’ve seen these pictures, I’ve seen close-ups and I’ve seen it from satellites but as you scroll around and watch the last 20 years’ progress, it is astounding and terrifying and moving to see the amount of destruction. And of course, I know that I benefit personally from this destruction but it is destruction. Similarly, we all know that lots of the Amazon rainforests has been cut down but you really can’t understand the depth and the scale of it until you watch it happen and are able to move all around Brazil and Bolivia and see how much of those forests are gone now. And then there’s the story of water, which of course, more people consume more of. Las Vegas and Dubai spreading across deserts, Saudi Arabia, with massive irrigation projects making the deserts bloom. Inland seas drying up, either because of drought or because of irrigation but in addition to being terrifying occasionally, it can also be a story of recovery.

Watching the forests take back the land that had been destroyed when Mt. Saint Helens erupted was particularly inspiring, though the nearby clear cutting was not. We humans have a profound and largely negative effect on the rest of the lifeforms of the planet. Science has, for a long time offered us these truths up on a platter in the form of data and numbers and statistics. But we are people, we are not computers and we are not particularly good at understanding what all of those data and statistics really mean. And it might be a better world if all policy was based on science, but it’s not. It’s based on the individual decisions and the individual feelings of individual people, like ME and like YOU. For me, watching all of this change with a very limited span of my own life is intense and it’s moving and it’s terrifying. We have learned a lot but we haven’t really acted on that learning.

And maybe that’s because we don’t really understand it. We know the numbers but we can’t see it, or we couldn’t see it. Maybe taking a look around the Google Earth engine, which I should say, is based on the NASA LandSat program, which is FANTASTIC, good job, NASA. It might give us all a better understanding of the realities that we face and if we really understand those things better, then the decisions we make will be better. At least one can hope. So YAY for NASA, YAY for Google, YAY for Science, YAY for understanding and hopefully, also in the near future, YAY, for action.