The last fifty years or so, the data I’ve shuffled through suggests a warming trend of about .1°C / 11-year or so solar cycle with about a .3°C difference between solar minimum and solar maximum, and then a whole lot of random variation (weather) on top of that which obscures the signals, but they are obtainable by averaging out the noise.
We can argue all day about whether it’s natural or man-made or what percentage of the warming is attributable to CO2 but I think the bottom line is that even if it is all man-made, the political will to do anything about it doesn’t exist.
It would seem in light of that the wise thing to do would be to start preparing for it, and here in the Pacific Northwest, one obvious change will be the amount of snow pack in the Cascades. We depend upon that snow pack not only for summer water but also for much of our energy needs in the form of hydroelectric power.
In preparation for that reduced snow pack, and also to prevent massive flooding in the event of winter precipitation coming down as rain rather than snow in the Cascades, we should build more and larger reservoirs, to both hold the run-off and provide summer water for our needs.
The other big adaptation we should make is how we use water for agriculture. Right now, if you look at central and Eastern Washington with Google Earth, you’ll see a pattern of circles in squares. These are aerial irrigation sprinklers in a square field. This is an extremely cheap form of irrigation, providing water is inexpensive, but it is inefficient.
With aerial sprinkler irrigation, first you loose a large percentage of the water to evaporation. But then without any monitoring of how far water is penetrating down in the soil, too much water is used, and the result of that is the leaching of minerals out of the soil which results in a number of bad consequences.
First, it increases the salinization of rivers, and where that water is used downstream for irrigation, of soil, which inhibits growth of many crops. The increased salinity of the water reduces the normal differentiation where it enters the seas and drives ocean currents.
Farmers then add phosphorus and nitrogen to their fields to get plants to grow. Those plants however are deficient in other minerals, which we as humans need in our diet. So one consequence of this poor farming practice is soil depleted in nutrients resulting plants also depleted in nutrients.
Then that phosphorus and nitrogen washes off into streams and rivers where it drives surface algae blooms depleting the water under the surface of oxygen. The result of this are streams and rivers where fish can’t survive and huge dead spaces in the ocean where only surface algae and anaerobic bacteria (which don’t rely on oxygen but instead derive energy by combining hydrogen and sulphur producing in the process hydrogen sulphide which is a strong contributor to what gives farts their odour (methane the main constituent of farts is odourless).
There is some evidence to suggest that at least one of the great mass extinctions of the past was caused by conditions that resulted in huge blooms of these anaerobic bacteria resulting in atmospheric levels of hydrogen sulphide which were toxic (anything above about 300ppm).
Suffice it to say that global warming or no, the irrigation situation is something we should address. The solution is drip irrigation with sensors placed at maximum root depth to turn off the water when it’s reached that depth.
There is no way of knowing the trend will continue as it has for the last fifty years, we could enter another Maunder minimum, or maybe a full scale nuclear war will result in a nuclear winter, but the odds I think favour a continuation of global warming.
Either way both of these things are good investments. If global warming halts, we can make more electricity to sell to California, and investment in more sane farming practices will preserve our soil and provide us with more nutritious food.