The media is full of stories about human-caused global warming.
But did you know there are large areas of the planet where humans are causing cooling?
Importantly, Washington is a prime example of our ability to massively cool the surface.
We do this by irrigating vast areas of eastern Washington and northern Oregon.
Consider a recent satellite image of our region (below).
The Columbia Basin should be a desert. Instead of desert or arid rangeland, we have irrigated vast areas, with the evidence being all the green dots and squares covering much of the basin.
Spraying water for irrigation causes massive cooling by evaporation. Or evaporation from a wet ground or wet plants results in strong cooling.
When the sun's rays hit the surface, much of that energy goes into evaporating water rather than warming the surface.
You can see the impacts of irrigation on temperatures quite easily. Below are some satellite images (so you can see where the irrigation is taking place) and high temperatures on a recent day (May 9) over a portion of the Columbia Basin (you can see the Columbia River). Generally, in the 70s over irrigated areas and low-80s over the nearby desert lands.
Here is a blow-up of the next day. Much cooler over the irrigated area.
The amount of irrigation in the Columbia Basin was rapidly increased in the late 1940s into the 1950s... and it had a profound impact on the temperature trends. Typically, irrigation results in 2-5 F cooling. Sometimes more.
At Othello, the mean high temperatures during summer actually DECLINED during the mid-century and stayed down.
Similar lack of warming in Ritzville.
So perhaps you can understand why fewer folks in Eastern Washington are concerned about global warming.😊
If you aren't impressed with the massive temperature experiment in eastern Washington, imagine the profound cooling impacts of the irrigation of large areas of the central valley of CA (see below).
Looking at a station there (Denar 3), you can see a similar lack of warming during the past century. Cooling due to the effects of irrigation played a role in this.
Cliff, what can you tell us about.the ozone layer and the ozone hole that we used to.read and hear.so much about? Is it.still.a serious problem?
ReplyDeleteIt would be interesting to see the temperature trends in Denair California from 1980 to the present. California started running much more water out to sea in the last 25 years, rather than use it for irrigation and the amount of land under cultivation was reduced. It got particularly dry after restrictions were placed on groundwater pumping in 2020. The 1980 to 2025 trends might show how water policy is affecting temperatures in California's Central Valley. They have been doing the reverse experiment.
ReplyDeleteSo ... what we've been building here in eastern Washington state for the last seventy years is the world's largest swamp cooler.
ReplyDeleteA very interesting case of human caused climate change, thanks Cliff. I wonder how the temperatures would vary if water usage was done by drip vs pivot/spray. The amount of water loss due to evaporation with overhead spray or pivot systems can be as high as 20% vs drip which can be less than 1%. Soil salinity is also an issue with highly irrigated lands in eastern Washington, leading to reduced crop yields, higher cost for farmers, and desertification. While crops like grapes and wheat thrives in these conditions, others like apples and hops can be a water hog. Crop diversity, rotation, and soil/water management are so important to maintaining productivity of these lands. Balancing agricultural needs with ecological considerations is crucial for the long-term health of these fertile lands.
ReplyDeleteWhat we conserve we can sell to Texas by pipeline. They will be happy to build it I think. Then use that money to subsidize affordable housing for low wage service workers.
DeleteBut what you haven't discussed is the huge cost of this irrigation in terms of probably our most valuable resource--water.
ReplyDeleteDon't forget what makes that water valuable is exactly what we are doing with it...turning it into food.
DeleteBe aware that I'm not overlooking the even more basic need for water to drink. That's just so much easier of need to meet in terms of volume. Total water consumption for both household use and irrigation combined works out to about 488 gallons per person per day. Drinking water is around 0.5 gallons per person per day.
https://waterdata.usgs.gov/wa/nwis/water_use/
For 200 billion dollars +/-, we could build ten or so 1200 MW nuclear-powered seawater desalination plants on the Washington coast, including a pipeline system to transport the fresh water inland, and so cover all the civil and agricultural water needs of the state at current levels of consumption for the next hundred years.
DeleteThat said, adopting a less water intensive means of growing our food might be just a tad bit cheaper than building a massive nuclear-powered seawater desalination system.
Betah Blocher, I agree that your second solution would be a tad bit cheaper. Either solution requires that we recognize the reality of current and future challenges.
DeleteAre there any studies on the climate impact of solar farms on Washington state weather ?
ReplyDeleteI still remember my elective of Atmospheric Thermodynamics (calculus based) decades ago. While Dr Mass just looks at Washington. I've been making this point regarding the Mississippi River Basin flood control and irrigation dams and reservoirs (also California Water Project). Places that were formerly dry deserts in the Fall now have rivers running through them year round = increased humidity = decreased diurnal temperature variation. Higher heat enthalpy in the atmosphere due to higher water content (humidity). Reservoirs evaporating in the summer causing local low pressure zones that attract violent weather (like tornadoes). Lots of fodder for PhD thesis. Diamond Valley Lake near Hemet CA is an example, convective evaporation pulling in smog into a formerly smog-free area (decrease in air quality sue?).
ReplyDelete