Guest post by Thomas Fuller
Before I start, I’d like to remind readers that as a guest poster, the opinions I voice here are not those of Anthony Watts, and should not be taken as having been endorsed by Watts Up With That.
I am going to propose an idea based on my position as a Lukewarmer regarding climate change. I fully expect to get a lot of criticism from commenters here, and I welcome it. My idea is new (at least to me), and if it is a good idea it will be sharpened by your criticism–and of course, if it is rubbish, best to know quickly, right?
I think the debate on climate change needs some new ideas and criticism too. So blast away–but please bring your A game. I neither need nor want to see the equivalent of ‘you suck, dude.’
Families, businesses and yes, even governments, need to make plans for the future. Those plans used to include assumptions about the physical environment, although most of those assumptions were passive acceptance of the status quo. However, it is now difficult to make assumptions because various theories of climate change and its effects have people wondering if their homes will be threatened by sea level rise, drought, hurricanes or floods.
Because of the competing number of possible futures (the IPCC has many scenarios and many more have been pulled from the science fiction rack and offered up to us), people are somewhat paralyzed by too many choices. I think it is time to recognize that all of use engaged in the debate about climate change are not doing the rest of the world any favors. We are making their life more difficult because they cannot make plans with any confidence.
If there is one dataset that I trust regarding the Earth’s climate, it is the measurement of atmospheric concentrations of CO2. It has been freely available for examination, it is replicated by measurements in more than one site, and in my mind survived criticism from people such as the late Ernst Beck. I trust the numbers.
The numbers show that concentrations of CO2 were 315 ppm in 1958, when Mauna Loa started measuring. Concentrations now are 390 ppm. That is a rise of 19%. The central question in climate change is, ‘What is the sensitivity of the earth’s atmosphere to a doubling of the concentrations of CO2?’ Is the atmosphere easily influenced by CO2, producing more water vapor and adding to temperature rise, or is the atmosphere largely indifferent? Despite protestations from both sides, the honest answer is we don’t know now, and we are not likely to know for another 30 years.
Temperatures appear to have risen globally, although the accuracy of the data is not yet fully determined. The rise since 1958 appears to be about 0.5 degrees Celsius.
If these were the only statistics available to us, we would quickly conclude that the sensitivity of the earth’s atmosphere to all human-related activities might well be 2.5 degrees Celsius. This would lead to the supposition that, if concentrations of CO2 rise to about 600 ppm, which certainly seems possible, that the Earth’s temperature will rise about another 2 degrees C. Since it’s based on measurement of temperatures, it can be presumed to include all the effects we are having on temperatures, not just CO2.
And I am arguing, no–proposing, that we do exactly that. Attempts to refine models and measurements have been unsuccessful and have served to heighten suspicion and muddy the debate. I have seen very credible arguments for sensitivities that are both higher and lower, but these arguments are based on data or models that have much higher levels of uncertainty associated with them, ranging from differing ways of measuring tropospheric temperatures to analysis of varves from Finnish lakes.
I don’t see undisputed data that will allow us to do better than the 40 years of good data we have now. So I think we should provide a ‘rough and ready’ estimate of 2 degrees C climate change this century to the public, business and politicians, so they can start making plans for the future.
It should obviously come with an asterisk and error bars, and should be presented as ‘crude, but the best we can really do at this time.’ Much like earlier and simpler climate models have often done better in handling projections of future climate, our rougher and cruder metrics may serve us better for now.
We need to stop throwing sci-fi fantasies out as plausible outcomes. We need to provide a range of outcomes based on measurements that we trust.
We also need not to be distracted by elements of the debate that have only served a political purpose. Current temperatures are not unprecedented. There was a MWP and a LIA. Sea level is rising at 3 mm per year. The ice caps are not going to disappear this millenium.
None of that really matters. Temperatures are rising, and more quickly than they have often in the past. (Yes, they have risen this quickly on occasion.) It is the speed of change and the numbers of people those changes will affect that are actually of more concern than the total temperature rise. The people in developing countries are actually more vulnerable than the last time there was a big quick rise–hunter gatherers didn’t have homes and could just move out of harm’s way, and they were few enough in number that they would not have been labeled ‘climate refugees.’
So, I call for all those involved in the climate debate to throw down their weapons, embrace this practical solution as being of use to the rest of the world, climb aboard the Peace Train and sing Kumbaya. Right.
No, have a look at this–tell me if it’s remotely possible that the skeptic community could sacrifice its current temporary, but very real advantage in the debate and agree that a rough metric that acknowledges warming but puts sane boundaries on it would be of use to the rest of the world.
Again, I’d like to thank readers who have made it this far for listening to a different side of the debate in a forum where you are more comfortable seeing the failings of your opponents exposed. If you find the gaping flaw in my logic, my idea can die quickly, if not quietly. If you see merit in my proposal, any indication of such would be warmly welcomed.