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“Everything is connected to everything else.” — Barry Commoner

Humanity is having an increasingly negative impact on our surroundings. We destroy habitas as we urbanize, which destroys native species of plants and animals. This destruction impacts the climate, water, and ultimately the richness of life, including our own. Each misstep creates a domino effect of non-linear consequences that are difficult to measure. These combined impacts are leading us into unknown territory, with humans, not nature, causing the sixth major extinction level event in the planet’s 4.5 billion year history.

The statistics included in “Consequences of Changing Biodiversity” should be alarming to any reader. The concentration of atmospheric carbon dioxide has increased 30% over the last 300 years, humanity is well on its way to using 70% of all fresh water for ourselves, and we have introduced invasive species for centuries that have dominated landscapes. We are responsible for the rise in temperature of the planet. Although the drama of melting glaciers recieves a lot of attention, one indirect consequence of a warming climate is the shift in the stability of the permafrost. This destroys the native mosses that protect the soil, allowing more invasive species to get a foothold and continue the warming cycle. This is also adding substantial amounts of methane, a greenhouse gas, to the atmosphere. Sadly, this is nothing new. Humans have been impacting our environment since we started hunting in groups, we are just getting more efficient. The article underscored the financial impact from the loss of diversity, which leads to a proliferation of invasive species, increased risks of forest fires, soil degradation, and erosion of agricultural productivity.

A Global Analysis of the Impacts of Urbanization on Bird and Plant Diversity Reveals Key Anthropogenic Drivers,” is slightly more optimistic. One surprise is that many cities included in their bird and flora study were predominately populated by native species; the taxonomy of the cities was regionally different and more diverse. A handful of plant species that were predominant across European cities were introduced to foreign countries before 1500, but the cities in 36 countries from the study did not share invasive species; this may change if we do not take action now. Urbanization has had a direct impact on the climate and biodiversity, which has led the extinction of native species. The article underlined the importance of preserving remnant vegetation that supports native bird populations; they have a symbiotic relationship.

Lastly, “Extinction by the Numbers,” may be read with mixed feelings of crisis and hope. Human activity, especially in the species-rich tropics, has gravely reduced the biodiversity of the planet. The slash and burn practices of agriculture has robbed the habitat of approximately 15% of the native species; the remaining 85% are subsisting in increasingly smaller and fragmented reserves; it is also removing our carbon sinks. We have reached a tipping point after which the extinction rate will increase dramatically. To prevent this irreversible loss, we must protect the remaining areas that have not already been destroyed. This will preserve the world’s biodiversity, even while we continue to lose it in urban areas. One positive way of viewing this finding is that as humanity migrates to cities we are moving away from rural habitats. Perhaps that natural shift in population as we flee nature for the gleaming concrete jungles may allow us to preserve the remnant areas; as long as we don’t exploit them to feed and clothe the city-dwellers.

Image Credit: World Wildlife Fund