What if global warming is actually an early symptom of the earth returning to a natural planetary Ice Age?

Question

My dad is a chemical engineer, and is highly skeptical of global warming. He believes that the earth is actually undergoing a massive climate change, and that global warming is merely the early warning symptoms of a coming Ice Age, which we won't actually see for thousands of years, much like what killed the dinosaurs. I don't really know what to believe, since both arguments seem logical - what do you think?

Answer 1

Ice ages are caused by "orbital forcing", changes in Earth's orbit that cause extended periods of longer or shorter winters in the Northern hemisphere. Since Earth's orbit can be computed for centuries into the past and future, orbital forcing can be computed and predicted with decent accuracy. But orbital forcing indicates that in the current interglacial era, Earth's temperature peaked 6000 years ago, and should be slowly cooling since then. (Here's a reference) http://www.sciencemag.org/cgi/content/abstract/207/4434/943

In other words, the natural cycle that causes ice ages has already peaked, and should be taking us in the cooler direction. Meanwhile the earth's temperature is rising rapidly: all ten of the ten warmest years on record have occurred since 1994.

The level of CO2 in the air now is higher than at any time in the last 23 million years, and the growth in CO2 shows no sign of slowing down. (Here's a graph).
http://www.grida.no/climate/ipcc_tar/wg1/fig3-2.htm

Answer 2

I agree with your dad. There was actually an ice age (a small one that wasn't very extreme granted) just recently in the 1800s called the Little Ice Age. All this global warming stuff could just be us warming after an ice age. Or this could be the side effects of an even bigger and longer ice age. But the earth has always had extreme cooling and extreme warming. I think it's funny that some people think we could mess everything up in less than 100 years. It seems a little improbable. 100 years isn't even a speck in the history of the earth.

Answer 3

Al Gore's movie "An Inconvenient Truth" was great, if you like fiction. Your dad is right, we are in an interglacial period. A warming between ice ages. The earth has had many warming and cooling periods in its history with no help from man. Atmospheric levels of C02 were much higher in prehistoric times. The Cambrian and Jurassic eras had concentrations 5 to 18 times higher than today, up to 7000 ppm. We are at 380 ppm currently.

Answer 4

Watch the Al Gore movie on global warming. Its called An Inconvenient truth. It was great!