The greatest influence of mankind on the earth’s ability to maintain a stable climate is the burning of fossil fuels (coal, oil and natural gas) and clearing land for agriculture and urbanisation. The problem with these activities is they increase the concentrations of greenhouse gases in the atmosphere. While they might have helped accelerate society’s success, digging stuff out of the ground and burning it or removing vegetation is not going to do us a lot of favours in the long run.

Greenhouse gases are capable of absorbing infrared radiation and their accumulation in the atmosphere traps and holds heat. This is what we call the enhanced greenhouse effect, the warming of the earth or global warming.

So it is not farting cows as some might think which is causing climate change.

Since the industrial revolution in the mid-1700s atmospheric concentration of carbon dioxide has increased by 40% from 280ppm (parts per million) to 406ppm in 2017. Ummm….so whether we like it or accept it, the evidence is pretty clear, right now, humans have a large part to do with climate change or climate instability.

Image: Scripps Institute of Oceanology

You might wonder if this really matters. Who cares right? At some stage we might have massive volcanic eruptions again which will send us into turmoil so really human impact is nominal, let’s all move on. Well we can think like that and put the head in the sand. But we don’t think future generations will be very happy with us if this is the strategy we plan on taking.

The last time the Earth’s atmosphere contained greater than 400ppm of CO2 in the atmosphere was back in the mid-Pliocene period 3 million years ago, about when the first homo habilis (tool man) arrived on the scene. The average temperature then was couple of degrees hotter and melting ice meant sea levels were about ten meters higher then today. We would count 400ppm in the middle bracket for what the earth can handle. Not life and death at this stage.

But what is worrying most is the rate of growth of CO2. We have not seen rapid growth such as now in the human existence. At current rates we will hit around 500ppm within 50 years and by 2250 closer to 2000ppm if not bought under control.

If we get to levels this high, what will happen, do we know? Let’s find out.