Thomas L. Friedman Quote

So what then is climate change? As the WMO defines it, climate change refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). The important thing to keep in mind here is that the climate changes because it is forced to change. And it is forced to change either by natural forces or by forces introduced by mankind. In other words, the climate varies naturally because of its own complex internal dynamics, but it changes because something forces it to change. The most important natural forces inducing climate change are changes in the earth’s orbit—which change the intensity of the sun’s radiation hitting different parts of the earth, which changes the thermal energy balance of the lower atmosphere, which can change the climate. Climate change, scientists know, can also be triggered by large volcanic eruptions, which can release so many dust particles into the air that they act as an umbrella and shield the earth from some of the sun’s radiation, leading to a cooling period. The climate can be forced to change by natural, massive releases of greenhouses gases from beneath the earth’s surface—gases, like methane, that absorb much more heat than carbon dioxide and lead to a sudden warming period. What is new about this moment in the earth’s history is that the force driving climate change is not a change in the earth’s orbit, not a volcanic eruption, not a sudden natural release of greenhouse gases—but the burning of fossil fuels, the cultivation of rice and livestock, and the burning and clearing of forests by mankind, which together are pumping carbon dioxide, methane, and other heat-trapping gases into the atmosphere a hundred times faster than nature normally does.