Not just climate

Over the last 100 years, global T has increased by about 0.7 oC, with some well-known decades of non-increase. For this to accelerate (as many expect) would require amplification by increasing water vapor. Or by directional changes to biological carbon cycling not considered here. Atmospheric water vapor is thus an important topic. We’ve discussed it previously but it has seemed inconclusive. A new publication is comprehensive.

Global Water Vapor Variability and Trend from the Latest 36-Year (1979 to 2014) Data of ECMWF and NCEP Reanalyses, Radiosonde, GPS and Microwave Satellite
Biyan Chen and Zhizhao Liu
J. Geophys. Res. DOI: 10.1002/2016JD024917

Not open access, but as always, options exist. Including paying Wiley (the publisher) money if you are so inclined.

One can get main messages for free, though:
Global water vapor increases 0.2 to 0.6% per decade,
Continental patterns include higher positive rates in areas of divergence, and negative rates in areas of convergence.

My opinion is that such global increases are small compared to what would cause positive climate feedback. It would not be surprising to have similar temperature trends, staying on our [CO2] increase path. Certainly ocean dynamics could change that, but we don’t understand them. Similarly the sun (energy source) could undergo (large-enough) changes, but it is also not predictable.

One additional degree (oC) is not a mainstream prediction, but it fits with CO2 and water vapor on the century scale. Given that more energy is a very defensible goal, and that renewable E is constrained in rates of increase, I expect CO2 increases in the range of RCP6 to RCP8.5.

From all that, it follows that +T may not be our most pressing concern. Food, water and energy certainly are. Ocean acidification (in context of food sources) may also be. Defending coastal areas of population and economic significance may also be. If we become a species interested in global biological diversity, many other issues arise.

Focusing on such goals, and less on +T, could turn out to be a tragic mistake. I get that. So, it makes perfect sense to keep checking thermometers. A decade or more with much faster +T (than we have had), should lead to reconsideration. Less burning, more stimulation of biological sequestration, consider geological sequestration.

Personally I’d very much like to see CO2 increase slowed. It is a novel, substantial change to the Earth system, and not something to mess with lightly. Only one inhabited planet! However, issues of food, water and energy for a growing population cannot be set aside, nor other candidate issues mentioned above. Were we smart enough, and rich enough to do everything, well, that would be a different world. In this world, people argue about everything.