The videos in the previous sections included several examples of adverse human and natural consequences of anthropogenic environmental change. Whether it be the negatives from the construction of a dam, the loss of a major water body, or the burden of having to deal with an invasive species.

For example, as the Brazilian Amazon rainforest is cleared for cattle and biofuels, new migrants are settling in these recently cleared areas. Since many of the migrants aren’t from this dense rainforest, they have not built up an immunity to many infectious diseases. Essentially, by clearing the forest and then settling in these areas, they are increasing their chance of acquiring communicable diseases.

Deforestation, irrigation for agriculture, and dam construction have also increased the exposure of humans to infectious diseases as they each improve the breeding ground for malaria-transmitting mosquitoes. Any warm area where there is slow moving or still-water is perfect for mosquito breeding. The still-water that backs up behind a dam is a great example of the conversion of a flowing river transition to a very still, slow-moving “lake” of water. Further, forested areas also do a good job of moderating local climates as they help keep areas cooler than they would be if there was no forest. Recently deforested areas then can cause local temperatures to increase and then lengthen mosquito breeding cycles.

Large, unsustainable population growth in urban areas of poorer countries, as noted in previous discussions on urban slums in developing countries, also have higher cases of water-borne diseases. Poor sanitation and primitive water treatment in these areas are the main culprits for deaths from infectious diseases in these countries. In many fast-growing, urban areas in arid regions, water is also a key concern, but instead, it’s the fact it is scarce and hard to find. Therefore, water scarcity is becoming an increasing concern across the world, no matter the income level.

Increasing environmental degradation can also be a key concern in the removing of natural protection from natural disasters and hazards. In the case of hurricanes, the destruction of tropical mangrove forests, vegetated dunes, and wetlands removes a natural barrier that protects inland areas from storm surge and flooding. Related to tsunamis, earlier destruction of coral reefs along the coastline of the island of Sumatra exacerbated the impact of 2004 Asian Tsunami and allowed the tidal wave to quickly move onshore and kill thousands of people. Finally, deforestation up-slope can trigger landslides down-slope, which has been seen throughout rugged, high-populated areas in California.