Scientists have mostly come to agree that the earth has entered a new phase of its existence. The previous stage, the Holocene, lasted about 10,000 years and was characterized by periodic ice ages. The new period, the Anthropocene, is characterized by the effects of a new significant driving force in the earth’s geology: humanity. Of course, humans have been around for a long time, but only within the past century did human existence begin to fundamentally change the nature of the earth.
The two most interesting changes are those to the nitrogen cycle and the carbon cycle. In the 19th century, when experts were making dire predictions about the earth’s inability to feed a rapidly expanding population, the nitrogen cycle was offered as a prime example. Farms need nitrogen in certain forms to grow food. So, food production is limited to the speed of the nitrogen cycle. To solve that problem, humans created nitrogen fertilizer. It worked. The nitrogen cycle was sped up immensely (see the chart below). Crop yields smashed through the “nitrogen barrier” identified in the 19th century. The earth now produces enough food to support seven billion people, a mind-boggling number for the 19th century experts.
The downside to manipulating the nitrogen cycle has been pretty minor. The most significant negative effect is the creation of “coastal dead-zones.” Run-off from farms over long periods of time washes the remnants of nitrogen-based fertilizer to coastal areas. This alters the chemistry of the soil, making farming nearly impossible. However, in most areas, this problem is insignificant, since most countries prefer to build cities and ports, not farms, on their coasts.
The other cycle that has seen a major change is the carbon cycle. The carbon cycle naturally moves more quickly than the nitrogen cycle. The carbon emissions caused by human alterations to the environment (i.e. burning fossil fuels, deforestation, etc.) are equal to only about 10% of the earth’s capacity to convert CO2 back into oxygen. The problem is that prior to human intervention, that cycle was already functioning at capacity. So, the human alterations have thrown the cycle out of balance.
Scientists continue to debate whether this is causing global warming. However, there is no question that human existence has fundamentally altered the carbon cycle.
Environmentalist rhetoric tends to suggest that if humans would just stop impacting the environment, everything would be fine. Enviro-sceptics (I may have just invented that word) tend to suggest that no matter what humans do, the environment can take care of itself. Both positions are wrong. They both ignore the fact that humanity is, and will continue to be, a massive driving force in the environment. That can be a good thing (as it has been for the nitrogen cycle) or a bad thing (as it has been for the carbon cycle).
Thus, humans should try to fix the carbon cycle problem. However, solutions should not be judged by how “green” they seem. Converting farms that produce food into farms that produce fuel for automobiles, for example, is a terrible idea, even though it seems “green.” Ethanol subsidies in America and Europe have reduced the global food supply and led to higher food prices in wealthy parts of the world and food shortages and riots in less wealthy parts. Advancing the efficiency of carrying power over long distances does not seem as “green,” but is much more promising as a solution to the problem. If electric grids could become significantly more efficient, massive solar fields in deserts might be able to power entire countries at a cost comparable to burning coal or natural gas. Also, finding artificial ways to convert CO2 back into oxygen on a large scale, though unpopular with environmentalists, should be part of the conversation.
In short, Republicans are wrong to pretend that carbon emissions have no environmental impact. However, environmentalists are also wrong to pretend that any impact that humanity has on the environment is necessarily bad. Humanity will continue to impact the environment whether environmentalists like it or not. The solution is to separate the positive impacts from the negative ones and act accordingly.