David R. Henderson  

Did Global Warming Help Cause California's Drought?

PRINT
What do "experts" say about tr... My Daughter the Juror...
President Obama and Governor Brown believe the science is settled and carbon emissions lead to droughts. Before we test the veracity of their beliefs, consider that many of the warmest places on Earth, such as rainforests, are both warm and wet. Further, some of the driest places on Earth, such as Antarctica and Siberia, are also the coldest. The coldest city in the world, Oymyakon, Russia, has a mean annual temperature of -15.5 °C and gets only 8.3 inches of precipitation per year. Antarctica's McMurdo Dry Valleys, obviously cold, are the world's driest locations. So we can't just assume that warmer equals drier.

Droughts are defined by reduced precipitation and increased evaporation, and California's 2011-2015 drought had both. What happened over the last three winters was a major reduction in precipitation (a reduction of 0.9 mm per day) with only a minor increase in evaporation (less than 0.1 mm per day). In short, the reduction in precipitation was an order of magnitude more than the increase in evaporation. "California lost essentially one full year of precipitation," according to Richard Seager, a climate model specialist at Columbia University's Lamont-Doherty Earth Observatory. "The [reduced] precipitation was the essence of this drought," added Marty Hoerling, a meteorologist at the NOAA Earth System Research Lab: "Farmers were praying for rain, not cooler temperatures."


This is from David R. Henderson and Charles L. Hooper, "Did Global Warming Cause California's Drought?" Defining Ideas, May 19, 2016.

Charley deserves more of the credit for this piece than I do. He tracked down virtually all the evidence. My main role was rewriting.


Comments and Sharing






COMMENTS (23 to date)
Jon Murphy writes:

Very interesting read, but I fear I am more confused than ever! I'm no scientist, but it seems like there remains great uncertainty on this matter.

I guess my question comes from this:

"Before we test the veracity of their beliefs, consider that many of the warmest places on Earth, such as rainforests, are both warm and wet. Further, some of the driest places on Earth, such as Antarctica and Siberia, are also the coldest."

It certainly is true. But I wonder how much vegetation plays into it? Are rainforests wet because they have lots of vegetation (and deserts dry because they have less)? Assuming that the answer to my question is "yes" (this could be a big assumption. Like I said, I don't know), then couldn't global warming indeed cause dryer-than-normal situations where the warmer air kills off local vegetation not used to higher temps? Based off the evidence in your article, that doesn't appear to be the case for California, but I'm thinking long-run.

Daniel Kuehn writes:

Can I ask you why you titled this blog post in this way? When you quote Obama and Brown in the article they never seem to suggest that higher temperatures cause it and they both use "climate change", not "global warming".

MikeP writes:

I wonder how much vegetation plays into it? Are rainforests wet because they have lots of vegetation (and deserts dry because they have less)?

Given (a) how fast vegetation grows when rains increase and (b) how very much vegetation on earth is easily explained by water obviously picked up over oceans -- think Florida, Indonesia, Brazil in the rain shadow of the Andes -- I think it's pretty clear that precipitation causes rain forests rather than the other way around.

Greg G writes:


I don't mean to be disrespectful here but I'll be looking to economists for the best understanding of climate science right around the same time I start looking to climate scientists for the best understanding of economics.

MikeP writes:

Indeed, when one sees how very, very badly climate scientists do economics, Greg G makes a good point.

The conclusion drawn by the article is mostly, "We don't know." That is a fair conclusion, but it is almost beside the point.

In the end, policy makers such as Brown and Obama cherry-pick the studies they want to support the policies they want and use them to make claims well beyond any scientific consensus and in direct contradiction to the IPCC. Nonetheless, they are not at all harmed by this with their supporters, who really do not pay attention to science or consensus, as evidenced by the legs that the ridiculous 97% claim continues to have.

David R. Henderson writes:

@Daniel Kuehn,
Can I ask you why you titled this blog post in this way?
You may. Check this quote from the source we linked to for Obama:
Scientists will debate whether a particular storm or drought reflects patterns of climate change. But one thing that is undeniable is that changing temperatures influence drought in at least three ways: Number one, more rain falls in extreme downpours -- so more water is lost to runoff than captured for use. Number two, more precipitation in the mountains falls as rain rather than snow -- so rivers run dry earlier in the year. Number three, soil and reservoirs lose more water to evaporation year-round.

What does all this mean? Unless and until we do more to combat carbon pollution that causes climate change, this trend is going to get worse. And the hard truth is even if we do take action on climate change, carbon pollution has built up in our atmosphere for decades. The planet is slowly going to keep warming for a long time to come. So we’re going to have to stop looking at these disasters as something to wait for; we've got to start looking at these disasters as something to prepare for, to anticipate, to start building new infrastructure, to start having new plans, to recalibrate the baseline that we're working off of.

Harold Cockerill writes:

I'm picturing Mr. Henderson dressed in burlap as Michael Palin stands beside him screaming "Burn Him!!!!!"

Ben H. writes:

So... you have triumphantly demonstrated that the drought was caused, not by "global warming" caused by CO2 emissions, but by "climate change" caused by CO2 emissions? A triumphant semantic victory!

Seriously, this post seems a bit confused about the basic science. "So we can't just assume that warmer equals drier." Nobody assumes that. Nice straw man, though. "Farmers were praying for rain, not cooler temperatures." That's fine; what farmers do or do not pray for is their own business. But the rain that they were praying for was – models and theory and empirical evidence suggests – absent in part because of anthropogenic climate change.

You really might want to talk to a scientist who actually knows something about this stuff.

Charley Hooper writes:

@Daniel Kuehn,

As David points out, Obama and Brown really talk about both climate change and global warming.

In this case, I think global warming (the atmosphere is heating) is a better term because it is more precise and it is what is driving climate change. Climate change is an output and it refers to everything: changes in temperature, precipitation, and drought.

So if we asked if climate change was causing droughts, the logic is somewhat circular: Are changes in droughts causing droughts? And it presupposes that droughts are changing.

This article highlights some laziness on the part of people talking about the climate. They start with the assumption that the atmosphere is warming due to greenhouse gas emissions. Then they rush to attribute every negative change in the climate to that extra warmth, even if the theories say there won't be any change or the change will be positive. Even a little thinking will show that a warming atmosphere will lead to some positive changes.

Khodge writes:

What I (think I) know about climatology is that there are no models that describe what actually happens, despite the intense focus on the matter in the last couple of decades. In my own mind, I have always wondered why melting of polar ice would lead to droughts.

MikeP writes:

But the rain that they were praying for was – models and theory and empirical evidence suggests – absent in part because of anthropogenic climate change.

Citation needed -- especially for that "empirical evidence" claim.

Certainly the AR5 that I'm reading through shows greater winter precipitation in California, even under worst-case projections. (See Box 12.1 on page 1041.)

Charley Hooper writes:

@Ben H.,

How do you reconcile your statement, "But the rain that they were praying for was – models and theory and empirical evidence suggests – absent in part because of anthropogenic climate change," with NOAA, which said the California drought wasn’t caused by global warming? Further, according to NOAA, with a warmer atmosphere, California should get more precipitation during its rainy season, not less.

"You really might want to talk to a scientist who actually knows something about this stuff."

Which scientists should we listen to? Those who say the drought was caused by global warming or those who say it wasn't?

Hans writes:

The way Barocko and Brown have been running their
respective institutions, both economies will
be dead with or without the aid of conclusive, climatic change.

The use of models by scientest and economist, have
lead to more confusion, mistakes and misleading labeling than a hobby store.

If economics is difficult to understand, then
our environment and it's weather clearly shows
not only the complexity but the limits of man's ability to draw conclusions and forecast
from them.

It is also paramount to remember, that between the two
extremes, cold by far out kills heat by a very large preponderance.

https://wattsupwiththat.com/2014/06/02/which-is-responsible-for-more-u-s-deaths-excessive-heat-or-excessive-cold/

bill writes:

@DRH: Is the second paragraph in your response to Daniel Kuehn your thoughts? Or a continuation of the Obama quote?
The paragraph that starts: "What does this all mean?..."

David R. Henderson writes:

@bill,
It’s a continuation of the Obama quote. Probably shouldn’t have had a line between paragraphs.

Dan W. writes:

California has experienced many droughts in its history. What made the latest one any different than the previous ones? The long term water management challenge for the state has little to do with carbon emissions. Yet there are politicians who pretend otherwise. Should that not be troubling? How many false beliefs can people have before there are real, serious consequences?

Venil A writes:

After reading this article along with another article from NASA's website, I believe that scientists may have found the reasoning behind the droughts. It seems like if no action is taken to reduce greenhouse effects and CO2 levels, then there is going to be an increase in global warming. This will lead to an increase in droughts, which is because of the tragedy of the commons. The tragedy of the commons is an economic problem where others try to get the greatest benefit from a resource, such as carbon emissions. As the population increases, so does the demand and this can be a big problem for the future. So if there is no government regulation on how much CO2 we produce, we are going to continue to use excessive amounts of it. Everyone will continue to look at their benefits instead of looking at how the carbon emissions are affecting the Earth as a whole, which can lead to excessive droughts. These droughts may not be affecting the economy as much, but the future growth of the economy may fail if we continue to ignore this issue being that one of our most abundant resources is water. Without water, our farmers are without a crop and we can soon be out of a food supply if we are not able to grow fruits and vegetables. Along with this article I have wrote a short piece on the NASA article I read if anyone would like to read it.
President Obama and Governor Brown believe that carbon emissions lead to these droughts and they actually might have some validity towards this due to a new NASA study which predicts that by the end of 21st century the American southwest and great plains is likely to experience longer and server droughts than at any other time in the last 1,000 years. A NASA Climate Scientist; Ben Cook predicts with the climate change many of these types of droughts will last for 20, 30, sometimes even 40 years even exceeding the duration of the long term intense mega droughts that characterized the really arid time period known as the medieval climate anomaly. How can a scientist like Cook predict this in the future one may ask. NASA scientists used tree rings to understand past droughts and 17 climate models in order to extend the drought information into the future. The models all tend to show a dryer world as the results of increased temperatures from human induced climate change. This is valuable since it is the only tool that we have in predicting future climate. How bad these future droughts can get has a lot to do on how much green house emissions humans generate in the coming years. The scientist looked at two different possibilities, first a business is usual scenario where worldwide greenhouse gas emissions continue on their current course. In this case, the future risk of droughts will rise to 80 percent however, if the world takes aggressive actions to reduce emission the model still shows drying but the trends will be less severe. These larger droughts will be much more harmful than the droughts that we are currently facing in California.

http://www.nasa.gov/press/2015/february/nasa-study-finds-carbon-emissions-could-dramatically-increase-risk-of-us

bill writes:

I'm looking to insulate my house. I can fill the wall cavities with fiber glass insulation or with gravel or dirt. Does it make any difference? Do some substances have greater or lesser insulating characteristics? Maybe I should fill the walls with snow since Antarctica is cold?

ThaomasH writes:
President Obama and California’s Governor Jerry Brown, for example, have concluded that climate change caused California’s 2011-2015 drought. In justifying his imposition of water rationing to deal with the drought, Brown said in 2015, “I can tell you, from California, climate change is not a hoax. We’re dealing with it, and it’s damn serious.” In a February 14, 2014 press release, Obama said, “Droughts have obviously been a part of life out here in the West since before any of us were around and water politics in California have always been complicated, but scientific evidence shows that a changing climate is going to make them more intense.” He added, “Unless and until we do more to combat carbon pollution that causes climate change, this trend is going to get worse.” President Obama has even reserved a special place on his website for climate change deniers who “are blocking progress in the fight against climate change. Find the deniers near you—and call them out today.”

President Obama and Governor Brown believe the science is settled and carbon emissions lead to droughts. Before we test the veracity of their beliefs, consider that many of the warmest places on Earth, such as rainforests, are both warm and wet. Further, some of the driest places on Earth, such as Antarctica and Siberia, are also the coldest. The coldest city in the world, Oymyakon, Russia, has a mean annual temperature of -15.5 °C and gets only 8.3 inches of precipitation per year. Antarctica’s McMurdo Dry Valleys, obviously cold, are the world's driest locations. So we can’t just assume that warmer equals drier.”

The quotes from President Obama and Governor Brown do NOT say “carbon emissions lead to droughts.” The clear meaning is that climate change is making droughts in California worse, worse that they would have been if the CO2 level in the atmosphere had remained at its 1750 level, for example. This could be right or wrong, but it has nothing to do with and is in no way contradicted by the observation that rain forests have high average temperatures and that eastern Siberia and parts of Antarctica are cold deserts.

Charley Hooper writes:

@ThaomasH,

The clear meaning is that climate change is making droughts in California worse, worse that they would have been if the CO2 level in the atmosphere had remained at its 1750 level, for example.

So you are agreeing that carbon emissions lead to droughts. How else are we to read this?

The Man from Vietnam writes:

"In certainty, California has less of a water supply problem and more of a water misconduct problem. This is demonstrated by the fact that we allow over 40% of our state’s water to gutter out into the Pacific Ocean. The California State Water Project is the largest multipurpose, state-built water project in the United States. The system was calculated and contracted to deliver 4,200,000 acre-feet but in an average year delivers only 2,300,000 acre-feet because many of the original planned features were never built."

More information can be found on: http://www.americanthinker.com/blog/2015/04/a_hot_water_issue_in_the_california_drought_discussion.html#ixzz3jtG9oGnp

J Mann writes:

As I understand the Obama administration argument, they don't engage the allegations that: (1) droughts overall have not appeared to become more frequent as the climate has warmed and (2) California has had many mega-droughts prior to man made climate change.

If I understand the administration, they argue something closer to the want of a nail - that if it weren't for climate change, this particular drought might have been weaker, or maybe stronger, or might hit someplace else. Therefore *this specific drought* can be blamed on climate change, as can all other weather on the Earth.

Charley Hooper writes:

@ThaomasH,

The rainforest and Antarctica examples were included to dispel the misconception that hot = dry and cold = wet. They are not central to the thesis.

Comments for this entry have been closed
Return to top