HotPlanet.org is a blog dedicated to the issue of anthropogenic climate change and how humankind may or may not adapt. We are now seeing things we've never seen before. Currently, carbon dioxide levels in Earth’s atmosphere are approaching 420 parts per million (ppm), mostly due to the burning of fossil fuels. The last time our planet was completely ice-free, the atmospheric carbon dioxide level was 450 ppm.

 

To see the trend of atmospheric carbon dioxide and how it is increasing visit NOAA's Global Monitoring Laboratory.

 

At the current rate of increase, about 3 parts per million annually, we will reach 450 ppm in ten years, in 2034. But because the Earth doesn't respond immediately to a climate imbalance, the planet may not be completely ice-free until about 2050.

 

How important are carbon dioxide levels?

During the last ice age, carbon dioxide levels were 180 ppm, and during our recent period of temperate climate they were approximately 280 ppm.

I believe we have already crossed a threshold, what some scientists call a "tipping point," and events have been set in motion. Climate change has now become irreversible, regardless of any future reductions in carbon dioxide emissions.

The planet is just now responding to the climate imbalance that existed 15 years ago. At the current level of 420 ppm we are seeing extreme heat waves of long duration and severe storms in various places all around the globe with no letup in sight, which only shows that carbon dioxide is a powerful greenhouse gas that cannot be underestimated. As carbon levels continue to increase, heat waves and storms will only get worse.

If we have crossed a threshold, and I believe we have, then what is currently happening is irreversible. The planet will continue to get hotter and hotter, and the only strategy for human survival is adaptation. It's going to be a wild ride.