I don’t believe in global warming, but . . .
I do conclude that the best available data indicate that it’s highly likely that it’s happening, at an unprecedented rate, and that humans are responsible for most of it.
It sometimes seems that the public debate about climate change is positioned as a matter of belief (you do or you don’t). From a scientific perspective this is not how you develop an hypothesis. You start with data — observations and measurements that can be verified by others who have the knowledge and skill to repeat the measurements. From the data you can test or develop an hypothesis or a set of hypotheses that might explain the significance of the data.
One of the datasets that got people thinking about climate change consisted of measurements of the concentration of carbon dioxide (CO2) in the atmosphere over time. Based on reasonably unimpeachable data from Mauna Loa, Hawaii, the concentration of atmospheric CO2 during my baby boomer lifetime has increased steadily from about 315 parts per million (ppm) to over 390 ppm as I write this. This is close to a 25% increase over a period of time that is not even a blink in geological time scales. For thousands of years prior to the beginning of the Industrial Revolution that got underway towards the end of the 18th century, again using relatively unimpeachable data from ice cores, CO2 levels were fairly constant in the vicinity of 260-280 ppm.
Well, so what? This leads to the question of what role CO2 might play in relation to temperature regulation on the surface of the one and only planet we can call home. The hypothesis here is that atmospheric CO2 plays a major role in trapping heat from the sun, analogous to the way in which sun’s heat shining through glass in an enclosed space can be trapped; hence the reference to CO2 as a “greenhouse gas.”
The current best estimate is that temperature of the earth has increased by about 8/10ths of a degree Celsius since about 1880. This may not seem like much, but it’s actually a significant increase and the effects of this increase are showing up now, especially — as predicted by the climate change models — in the higher latitudes (i.e., in the colder regions of the planet).
Now CO2 is a normal and necessary gas for life on earth. It is used by photosynthetic organisms on land and in water to produce the organic molecules they require to live, grow and reproduce. They also form the basis of the food chain that we (and all other organisms that can’t manufacture their own food) depend on for survival.
The fundamental processes relating to circulation of CO2 among living organisms — as any biology student knows — are photosynthesis (CO2 + H2O + light energy –> CH2O + O2; i.e., carbon dioxide plus water plus light energy yield energy rich organic molecules [e.g., sugars] plus oxygen) and respiration (CH2O + O2 –> CO2 + H20 + energy).
Normally it could be expected that these processes would be more or less in balance and this has been pretty much the case throughout most of the development of human civilization; however, since the Industrial Revolution, we have been burning massive amounts of carbon-based fuels that had originally been formed through the process of photosynthesis but had become sequestered millions of years ago in deposits of coal, petroleum and natural gas (the “fossil fuels”). These fuels had not been used previously to any great extent during the course of the development of human civilization and were not part of the carbon cycle on the earth’s surface. In my lifetime (i.e., since the end of World War II) global annual carbon emissions have increased from less than two billion to about nine billion metric tons. This amount of CO2 is more than the earth’s photosynthetic organisms and oceans can absorb (and sequester for long-term carbon storage in substances like wood), so the CO2 is building up in the atmosphere because it has nowhere else to go.
So what can we do about this? The good news is that there is quite a lot we could do by reducing our combustion of fossils fuels through conservation measures (which also extend the availability of these finite resources to future — and maybe smarter — generations) and the use of alternative energy sources that do not emit CO2.
The bad news is that this is a global issue and effective action demands a global solution. Sadly, to date, the human family has not demonstrated the collective political will or resolution to undertake more than relatively small efforts to address the issue. Couple this with a rapidly increasing global population and the increasing energy demands of developing economies (with little in the way of an offsetting reduction in the energy demands of developed economies) it appears that for the foreseeable future global warming will continue and will be accompanied with a concomitant increase in human misery, especially in the more fragile and disadvantaged parts of the world. Put another way, those who contribute the least to creating the problem will suffer the most.
So the critical question becomes: How bad does it have to get before there is an adequate collective will to take action?
[Originally posted on Blogger 10 September 2011]