free debate

June 20, 2009

Defining Climate Change

We've heard it all over the news and the web. "Humans are causing global warming." "We'll make ourselves, and everything else on the planet, go extinct!" These doomsayers claim that only immediate action will save our planet from ending up like this:
However, a lot of these websites claiming doom and destruction just refer to "scientists" providing claims or cite CO2 as an exclusive cause for "global warming." In truth, though, the situation is more complex.

First off, "global warming" is an extremely inaccurate term. The planet Earth is not uniformly warming up. Some areas will get warmer, while others will get cooler. Therefore, in referring to the changes in global temperature, the term is "climate change," not "global warming."

Second, climate change is nothing new to the planet. Throughout the planet's history, the temperature has changed. In the Cretaceous, for instance, there were no polar ice caps. The Earth regularly warms and cools for various reasons, including:
  • Eccentricity: As the Earth orbits the sun, the shape of the orbit, as well as the tilt of the planet, change somewhat. Because of this, the amount of heat reaching the planet changes, which can cause ice ages, based on a theory by Milutin Milankovitch.
  • Sun Intensity: This is pretty self-explanatory. As the sun fluctuates, it may be more or less powerful for a period of time. This can also cause changes in the global temperature of the planet.
  • Volcanic Eruptions: The release of particulate matter and greenhouse gases into the atmosphere when volcanoes erupt can also affect climate temporarily. A time interval with a lot of volcanic activity can push a more lasting shift in the climate.
  • Ocean Currents: A large conveyor belt of circulation in the oceans moves cool water from the poles to the equator, and warm water from the equator to the poles. As global temperature shifts, this current may become weaker, changing climate regionally.
  • Greenhouse Gases: And this is the one everyone is concerned about. Gases like carbon dioxide (CO2), methane (CH4), water vapor (H2O), and nitrous oxide (N2O) all can capture infared radiation and prevent it from escaping the atmosphere. This leads to a build-up of heat, the greenhouse effect.
So, in a nutshell, that's what climate change is, and what causes it.
In the next installment: the Human Factor

Credit: EPA