Desertification never describes the presence of a natural desert. It is the process of making an area look like a desert, having its characteristics while it should not. It is caused by acid rain, deforestation and the setting of fires. Also, because of overgrazing when plants start to grow again after a fire. Most of the times there is a combination of some or of all those factors, which are all connected with human activities.

During desertification, many animal species die or lose their natural habitat. Plants disappear and face extinction. Valuable sources are lost, as fewer plants produce less oxygen. Thus, it is connected with global warming and climate change. Moreover, desertification often results in floods, as there are no trees to keep the soil steady with their roots. Floods harm both natural ecosystems and human properties, sometimes including death tolls.

Consequently, desertification is a very serious problem and should be solved. Laws ought to be passed in order to decrease the amount of trees cut down and of wooden products one can buy. Carbon dioxide emissions, by which acid rain is caused, must be reduced to prevent soil erosion. Authorities have to protect forests, by organising fire brigades and immediate reforestations. Animals that graze should be kept away from burnt areas where plants have just started to grow again.

Fires are rather often in Mediterranean ecosystems, due to the mild winter and the long dry summers. High temperatures and drought, in combination with dead leaves on the ground, often cause fires. But when referring to a natural process, often means every eight to ten years.

Mediterranean ecosystems have developed ways of regeneration within less than ten years, because the species living there have adapted themselves to the periodical presence of fire. Most roots, for instance, remain alive and plants grow up again.

But no ecosystem can regain its previous healthy state if human sets fires almost every year. And that is what happens nowadays, for various reasons. Burnt forests provide humans with the space needed for new fields, farms and houses. But the price for doing so is high. Many animals die or lose their natural habitat. Many species face extinction. Moreover, having less plants means that less oxygen is produced.

Consequently, it becomes obvious that measures should be taken so as to protect forests from fires. Stricter laws ought to be passed, and especially against arsonists.

When household and industrial wastes are disposed into the water, they increase the quantity of germs in it. Germs threaten the health of the organisms living in the water, drinking it or feeding on organisms that live in it. Moreover, huge quantities of nitric and phosphoric salts enter the ecosystem. Phytoplankton, the tiniest sea organisms that can photosynthesize and depend highly on those salts, start to grow in population at top speed, consuming oxygen. As a result, zooplankton which feeds on phytoplankton starts to increase in numbers, again consuming oxygen and producing carbon dioxide.

After some time, during which those small organisms continue to consume oxygen and produce larger amounts of carbon dioxide, there is not enough oxygen to sustain bigger organisms, like fish, who actually die of suffocation.

Lakes are the most usual ecosystems harmed by eutrophication. Oxygen cannot be easily diminished in the sea, and the movement of the water in rivers transfer the salts else where. The most common sign of eutrophication is the waters having a deep green colour. And as human wastes increase, ecosystems become more fragile and their living organisms more vulnerable to suffocation.

Consequently, one of our first priorities, as far as those ecosystems is concerned, is to find alternative ways of removing our industrial and household waste, so that it doesn’t end up in the water. The top priority, needless to say, is to reduce those wastes.

According to a recent published report, by Benjamin Halpern and his colleagues at UCSB’s National Center for Ecological Analysis and Synthesis, over 40% of the world’s oceans are heavily impacted by anthropogenic activities. Only a few, “if any”, areas are unaffected.

The report have taken four years to compile and resulted in 17 models of the earth. Each of the different models shows the damage caused by human activities such as pollution and fishing. The different models have then been merged into one showing the global effect (see image).

Benjamin Halpern explains, on the UCSB website, the process he and his colleagues followed to make the composite map:

“1. We gathered or created maps (with global coverage) of all types of human activities that directly or indirectly have an impact on the ecological communities in the ocean’s ecosystems. In total, we used maps for 17 different activities in categories like fishing, climate change, and pollution. We also gathered maps for 14 distinct marine ecosystems and modeled the distribution of 6 others.

2. To estimate the ecological consequences of these activities, we created an approach to quantify the vulnerability of different marine ecosystems (e.g., mangroves, coral reefs, or seamounts) to each of these activities, published in Conservation Biology, October 2007. For example, fertilizer runoff has been shown to have a large effect on coral reefs but a much smaller one on kelp forests.

3. We then created the cumulative impact map by overlaying the 17 threat maps onto the ecosystems, and using the vulnerability scores to translate the threats into a metric of ecological impact.

4. Finally, using global estimates of the condition of marine ecosystems from previous studies, we were able to ground-truth their impact scores.”