There are people out there who still doubt the gravity of global warming, including politicians who should know better. Ignorance is no excuse. Climate science commentator Charles Nagy lays down the irrefutable facts.
Just suppose you decided to conduct an experiment to test the law of gravity yourself, rather than take advantage of the many years of experimentation and analysis conducted by countless scientists. Suppose further, that you decided to step off the Empire State building in New York as your method of experimentation. Suffice to say, you’d only do this once.
However, assuming that you could do this experiment over and over again, you would find that each and every time, you would slam into the pavement below at around 122 MPH – the terminal velocity of a human being. There is no doubt as to the outcome of this experiment. Science has determined over the course of the past 300 years or so how gravity influences falling bodies and can predict the actual speed of your demise with unerring accuracy.
Isaac Newton figured out the Law of Gravity in 1687. Gravity is now an established scientific fact not worth debating.
Similarly, back in 1824, it was shown that Earth’s temperature would be much lower if it lacked an atmosphere. By 1859 it was also clear that the main gases that trap heat within the atmosphere, are water vapour and carbon dioxide (CO2).
In a nutshell, the reason why CO2 has this quality is that it allows high frequency radiation from the sun to enter the atmosphere and warms up the land and oceans, which then try to radiate this heat back into space as low frequency infrared radiation (heat). CO2 blocks this, so much of the heat remains in the atmosphere. No serious scientist now doubts the heat trapping qualities of CO2, and that increasing its concentration in the atmosphere will cause surface temperatures to raise. This is as much a scientific law as the law of gravity.
So what exactly are climate sceptics arguing? Some of the least scientifically adept would say CO2 is not a greenhouse gas – an argument tantamount to saying gravity doesn’t exist. Other more sophisticated sceptics claim that despite all evidence to the contrary the Earth is not warming, and in any case even if it is, the warming is very “gentle” and not due to human influence. This is akin to claiming that obesity is not caused by over-consumption of donuts and Coke.
So let us carry out another little thought experiment to illustrate. Using thermodynamical analysis – thermodynamics is as well established in science as is gravity – it is possible to deduce the temperature of the planet if it had no greenhouse gases. This comes in at around minus 18 degrees Celsius. This would result in a snowball planet with ice covering every inch of surface area, with no life possible. The pre-industrial level of CO2 was around 280 parts per million (PPM), which was enough to keep the temperature of the planet constant at around 15 degrees average for the past 10,000 years. The current level is around 410 PPM. This is an increase of 46% from the 280 PPM – a drastic increase that has a noticeable effect on planetary temperature.
Furthermore, the planet wanders between glacial and interglacial states over a period of around 100,000 years. We are currently in an interglacial period, having just come out of a glacial period 20,000 years ago. During this period, ice sheets covered the Earth, reaching down to the border between the USA and Canada, and halfway down Europe. These ice sheets were a mile high and sea levels were 200 to 300 feet lower than today. That is a serious amount of ice. Ice age CO2 concentration was around 180 PPM, so just 100 PPM was responsible for such a huge change. And what is the average temperature differential between now and when we were deep in the glacial age? Just four Degrees Celsius.
Let me repeat: just 100 PPM (35%) less CO2 and four degrees lower temperature was enough to have massive one mile high ice-sheets dominate the planet. We are now 130 PPM over the pre-industrial level. If a 35% decrease in CO2 is enough to cause mile high ice sheets, what is 46% in the opposite direction going to bring?
Just like our hypothetical one-off experiment with gravity, we are currently conducting a one-off experiment on Earth and all its inhabitants – with potentially the same outcome. That increasing green house gas concentrations will raise the temperature of the planet cannot be denied. The science is as solid as the law of gravity. We even know roughly the degree of temperature change we will be dealing with.
The Gravity of Global Warming should weigh heavy on us all!
Given the effect of such a temperature change on the planet in ages past, we can infer that it will be catastrophic for our highly technical civilisation. We also know that like our suicidal amateur scientist above, it is likely to be a one-way trip. CO2 dwell time in the atmosphere is around 1000 years, so if we cannot somehow remove the excess CO2 then the planet will keep on heating up – especially as we have made no attempt to rein in our CO2 production. Nor do we currently have a reliable method that can be scaled up to remove CO2 from the atmosphere. But because most future temperature projections stop at the year 2100, people subconsciously believe that, “OK, we can deal with two or three degrees” – a dubious conjecture to start with. And that is not how it is going to play out.
Two to three degrees – if we do nothing soon, it will probably be four to six degrees – will be just the start. Absent some giant geo-engineering project, the temperatures will keep going up and up and up for the next 1000 years.
Can we deal with that?
PS> Don’t just take my word for it – here’s what NASA had to say about it twenty years ago.