Dr. Ricky Rood's Climate Change Blog

Hot and Smelly

By: RickyRood, 6:00 AM GMT on June 27, 2012

Hot and Smelly

For the second time in two weeks I have witnessed the explosive development of a wildfire here in Colorado. I wrote to Jeff Masters about the High Park Fire outside of Fort Collins, which was, say, 40 or 50 miles away from where I saw it start. Today’s fire in Boulder is just outside of the National Center for Atmospheric Research’s (NCAR) Mesa Laboratory. I was out in a field about 6 miles away and there had just been a small thunderstorm where rain almost fell to the ground. In less than 30 minutes the fire covered almost 300 acres; this is an explosion. So far all of the firefighting has been from the air because it has been too furious to fight from the ground.

Here is an amazing picture that I saw in the Boulder Daily Camera, that was taken by Chad Baudoin and posted on Twitter

Figure 1: Eruption of Boulder County, Colorado fire near NCAR taken from Denver. Credit: Chad Baudoin posted on Twitter. (larger)

There are galleries of pictures and videos from the Boulder Daily Camera.

The fires in Colorado right now are overwhelming. 100s of houses have been lost in the state, and the pictures of the Waldo Canyon Fire in Colorado Springs are simply frightening. (sorry about the advert) (Denver Post Story).

The past few days have been relentless. Denver has seen temperatures above 100 F for 5 straight days, and it was 105 F today. At the weather station closest to where I live, the thunderstorm that started today’s fire stopped the temperature rise at 97.5 F. The dew point was in the high 30s. The ground temperature in the garden about 110 F.

Tonight it all smells of smoke again. It is hard to sleep when the house is 88 degrees and the air smells of smoke. You constantly think of fire. And, in the grand scheme of things, I just linger as an observer on the edge of fire surrounded by still wet fields.

For the last two nights, the moon has set behind the Rockies as a glowing red crescent in the smoky sky. The sunset tonight had a rainbow in the smoke. Sadly, no Wunderphotos from me.

I will get back to my normal form with my next entry.



Difference Between Night and Day

By: RickyRood, 5:20 AM GMT on June 20, 2012

Difference Between Night and Day

Somewhat to my aging surprise, I have resided in several states: North Carolina, Florida, Virginia, Maryland, Michigan and Colorado. Plus, I spent a year in Livermore, California. This is a climate blog, so I will get quickly to the subject, temperature. What I remember about the Florida air was that it was cleaner, had a remarkable pulse of sea breeze thunderstorms and lightning in the summer, and in the summer, it was not as hot as people complained about – at least during the daytime. I have spent far more time over a 100 degrees F in North Carolina, Virginia, Maryland, Colorado, and California than I have in Florida. Of course, this is the humidity not the heat.

When I was immersed in this heat, I used to think of the air as “heavy.” That’s the sort of thing that writers talk about, thick Southern air redolent with magnolia and sticky in mystery in the graveyard next to the swamp. So I used to think of this Florida air as so heavy and thick that it just couldn’t get hot. Of course, this is not a very smart way to think about heat and humidity. As I recall, water, two hydrogen atoms plus an oxygen one, is lighter than either the nitrogen or the oxygen molecules that make up most of air – not to mention that weighty molecule made of two oxygen atoms and a carbon atom.

Some time ago now I did a series of articles called Bumps and Wiggles. The sixth one in that series was called Water, Water, Everywhere and discussed the important role of water as a greenhouse gas. We have a lot of water; the oceans are full of it. Water evaporates from the ocean and lakes and the soil, and gets into the air. Warmer air holds more water, hence, if the temperature goes up, then we expect there to be more water in the air. Since water is a greenhouse gas, we would increase greenhouse warming with the addition of water vapor.

So back to Florida - there’s a lot of water in the air, but I stated above that my experience was that in the summertime during the heat of the day, it was not so hot. But nighttime is a different story in Florida. It does not cool down that much. There is a simple way to think about this. Daytime heating is strongly related to the presence of the Sun and direct heating by solar radiation. This radiation is primarily visible light. Carbon dioxide and water are not the primary absorbers of visible radiation. So this visible radiation goes through the atmosphere with relative ease. It heats the surface, and it is converted to thermal or infrared radiative energy. It is this infrared radiation that water and carbon dioxide absorbs and emits, acting like a blanket, and warming the surface. The infrared radiation is emitted day and night, and with the absence of the Sun at night, the greenhouse warming of the water vapor becomes prominent.

This relation between water vapor and daytime and nighttime temperatures is well known, and it influences decisions about where we live, and perceptions of nice and not so nice “climates.” Deserts are dry and notorious for wide swings between daytime and nighttime temperature. The lack of water vapor and clouds allows, at nighttime, the surface of the Earth to cool to space with some effectiveness. During the daytime it gets very hot. Look at the temperatures of Tucson and Phoenix, Arizona; they are frequently above 100 F. Florida has far smaller differences between daytime and nighttime temperatures. (Some day I will tell you about my July hike in the Anza Borrego Desert. Today, I will only mention that while planting this afternoon, 20120619, in Colorado the very dry dark soil was so hot I could not kneel on it. Happy plants.)

Last year, 2011, we had historical heat in large portions of the U.S., and it was notable that the nighttime lows were extraordinary and quite moist. (Rood from 2011). A couple of blogs ago, I mentioned the observation that there was a strong trend showing increase in nighttime lows – that is, it is not getting as cold at night as it used to (Heads and Tails: Still thinking about Spring 2012). This is suggestive of an increase in water vapor keeping the nighttime temperature high, but that is not the entire story. Because of the water vapor increase, there is more likelihood of clouds, and clouds have a stronger greenhouse effect than water vapor.

So I started this blog talking about Florida, and how the daytime temperature did not seem as hot as I might have expected. And, of course, I mentioned my not so bright idea of the air just being too laden with water. So I need to go back to that and think about that a bit. If there is water available to evaporate into the air, then it takes energy to convert that water from liquid to vapor. In the Florida afternoon, it gets hot, there are a lot of updrafts and downdrafts which enhance mixing, and there is a persistent flux of water from the ground and plants into the air. This evaporation consumes some of the heat, and effectively, limits how hot it gets. At night, of course, as the air cools, the water condenses, releasing some of that heat back – contributing to those warm nighttime temperatures.

Now I have a couple of threads wandering around here. I have water vapor and clouds acting as a greenhouse and keeping nighttime temperatures high. I have water vapor evaporating in the Florida afternoon and keeping daytime temperatures, in some sense, moderated. That is, it does not get as hot as one might imagine. I have introduced this idea of nighttime minimum temperatures increasing, and I have talked about these temperature increases being related to water, not carbon dioxide.

So, let’s answer the carbon dioxide question. If the climate were stable, that is, the Sun did not vary, carbon dioxide was not increasing, there were no volcanoes, etc. then water would still cycle back and forth between ice, liquid, and vapor. There would still be impacts on nighttime lows and daytime highs. Water vapor would be important to regional climate differences, like the difference between Florida and Colorado. We can reason that in this stable climate, over the course of the year, there would be a certain average amount of water vapor in the atmosphere. In this stable world, this average amount of water vapor in the atmosphere would be stable. When we add carbon dioxide, we make it a little warmer and the atmosphere can hold a little more water. We see here that a water vapor increase follows from carbon dioxide increase, greenhouse warming building on top of greenhouse warming.

That said, it is also possible to change the water regionally, for instance by irrigation. In this case there are regional impacts on the temperature that are not caused by carbon dioxide. Opposite of irrigation, there might be drying due to agriculture. From the discussion above, we might expect surface irrigation to contribute to nighttime warming and drying to contribute to daytime warming. In either case this is “climate change” caused by the activities of humans, but it is not directly caused be carbon dioxide increases. Such regional changes are very confounding to attribution studies of regional warming and cooling, and also cause of controversy amongst scientists and others who sometimes fight over one mechanism versus the other.

What I have described here has the potential for substantial complexity. If we just had carbon dioxide, no water, it would be trivial, at least in might be trivial, to understand warming. Adding water, ice, liquid, and vapor, makes the problem more complex. Then the fact that when water vapor condenses in the atmosphere it makes clouds – well, it’s a lot to manage. But, it might be reasonable to expect water vapor to have different effects on nighttime lows than daytime highs. It also means that great changes to the surface water budget, like the Dust Bowl and irrigation in the Corn Belt, would be expected to have important impacts on regional climate. I plan to address this more completely in the next couple of months.

I will end this entry with reference to a paper that in the march of climate science is getting old, Kukla and Karl, 1993, Nighttime Warming and the Greenhouse Effect (from Rood’s Class Website ) It is historically interesting to me. This paper talks about the decrease of day to night temperature variability that is occurring due to increases in the nighttime minimum. There are in 1993 and in the decade following many papers investigating this subject. The paper is written at a time when the greenhouse warming due to carbon dioxide had not so clearly emerged as it has today. It was also written when climate models were at least 2 full generations prior to today’s generation. That means that clouds, aerosols, and land-surface processes were not represented at the same level of fidelity as they are now. The paper marches through different mechanisms, setting the foundation for future investigation. A good read for readers of this blog.

As I understand it, heat wave coming to the East - Delaware, Maryland, Virginia, southeast Pennsylvania and southern New Jersey are expecting the heat index to reach from 100 to 105 degrees on Wednesday and Thursday (June 20 and 21, 2012). New York, Vermont and Massachusetts will see near record-breaking temperatures. Here in Colorado, Wednesday will be cooler, but Thursday back up to nearly 100. Keep an eye on those nighttime lows. Stay hydrated, especially if you are trying to use a fan to stay cool. Fans cool you through evaporation, and dehydrate you faster.

I am expecting this summer to offer many opportunities for such discussions. Here in Colorado, a land of scant water, I have just experienced both record daytime highs and record warm nighttime lows in the past couple of days. In the grand scheme of things, that’s relatively rare.


Figure 1: Self explanatory. Credits – several times removed, but taken from Planetsave. Isn’t the Web Wonderful?

Climate Change Attribution Climate Change Climate Impacts and Risks

Updated: 2:20 PM GMT on June 20, 2012


The Dust Bowl and Sea Level

By: RickyRood, 4:56 AM GMT on June 11, 2012

The Dust Bowl and Sea Level

One of my favorite blogs in my portfolio is Science, Belief and the Volcano. In that blog I referenced The Worst Hard Time: The Untold Story of Those Who Survived the Great America Dust Bowl by Timothy Egan. I will use this later in this blog.

Several people brought me the news that some in North Carolina want to fight the predictions of sea-level rise. Likewise several have mentioned Colbert’s piece on this initiative. According to the news article several North Carolina local governments have “passed resolutions against sea-level rise policies.” Here is an interesting blog in Scientific American on the proposed law.

Here is a link to the proposed bill. There is a provision that if sea-level rise projections are needed then

“These rates shall only be determined using historical data, and these data shall be limited to the time period following the year 1900. Rates of sea-level rise may be extrapolated linearly to estimate future rates of rise but shall not include scenarios of accelerated rates of sea-level rise.”

The bill also discusses, at length, a variety of programs related to building setbacks for coastal building. Obviously, perhaps, “accelerated rates of sea-level rise” are not good for new or old construction on the coast. Not good for the insurance companies either. (and here as well)

So back to the Dust Bowl. The Dust Bowl was comprised of the Oklahoma and Texas Panhandles, and the neighboring parts of Kansas, Colorado, New Mexico, and Nebraska. Three towns in the center of this region are Boise City and Guymon, Oklahoma and Dalhart, Texas. The following map from mapshop.com sets the scene.

Figure 1: Map of the U.S. Dust Bowl Region in the 1930s, from mapshop.com

It is hard to write in a paragraph the extremes of the degradation of the land; weather, hot and cold; dust drifts; mud falling from the sky; houses and villages buried in the dust; and a whole set of plagues and illnesses that killed and drove away people. The cause of the Dust Bowl was a convergence of many factors ranging from farm policy and farm practices; to overly ambitious civic and corporate growth; to extreme heat, drought, wind, and winter storms. From the perspective of the climate scientist, it becomes an interesting question of once the conditions of the Dust Bowl were realized, how much did the lack of vegetation and soil moisture contribute to the perpetuation of the extreme weather? (See, for instance, Schubert et al., Science, 2004)

There was also a certain element of fate. When there was a burst of development and expansion in the Dust Bowl region, there was also a period of above average rain. At some level this seemed to be known at the time, and there were those, including companies, who argued that the development of the land, the plowing, steam from the train, the disruption, was actually the cause of rain. This acceptance of the idea that people were having a positive impact on the weather, and essentially the climate, would ultimately stand in stark contrast to their denial and rejection of the notion that their behavior could be having a negative effect.

There are two points that I want to draw from the The Worst Hard Time. The first was the attempt to reframe the dust storms in support of building, development, and community. In Dalhart, Texas, the town paper, the Texan, started a campaign with a tribute to the sand storms as majestic events that should draw people in to see the wonder. There was outrage that the East Coast and national press was trying to slander the town and the region – trying to discredit the people of the region by blaming them for the degradation of the land and dust in air. There were those in the East saying that those in the Dust Bowl were exaggerating their situation trying to extort money from Washington.

There was in this campaign a quest to make the dust storms majestic and divinely positive events, a rejection of both the obvious collapse of people and towns and of the increasing scientific evidence that at the very core of the collapse was the behavior of people. From the Texan, John McCarty, wrote that people should

“view the majestic splendor and beauty of one of the great spectacles of nature, a panhandle dust storm, and smile even though we may be choking and our throats and nostrils so laden with dust that we cannot give voice to our feelings.” ( The Worst Hard Time, page 185)

There was something of boasting of bigger storms in other states. Then there was blame that dust of other states was the cause of their grief.

There was rejection of the growing scientific evidence that the breaking of the soil stabilizing root structure of the native grasses was at the foundation of the collapse. And while this science that challenged the will of the people was rejected, anecdotal evidence that was attributed with the strength of science was used when it matched their will or need. Of especial note was the observation that when there had been a rush of people to the Dust Bowl region, there had been both rain and a World War. For a hundred years people had associated rain with war. Therefore, towns would bring in experts with cannons and explosions. A literature developed on using dust as mulch for crops.

The second point I want to make is the depth of the denial or suspicion of the mounting scientific evidence that the behavior of humans was responsible for the degradation of the soil and the sky full of dirt. This was not only a position held by those with a belief that man could not, while working God’s will, cause such damage (see here, perhaps), or those with a vested interest in real estate and business, but also, President Roosevelt and many in Washington who did not want to believe that America’s destiny to make the whole country productive was challenged by pursuit of that destiny. Ultimately, however, Roosevelt accepted the scientific foundation and massive programs to stabilize and reclaim the land were initiated. Many would argue, I included, that even today we struggle to sustain this reclamation and recovery.

So I am asked about how I respond to those in North Carolina who want to reject the predictions of sea level rise – to prescribe, by law, how such predictions might be made. I start with saying I have more experience on the coast of North Carolina than most. I spent many years in Craven and Carteret County on the mouth of the Neuse River. My father had small pieces of land from Long Beach to Kitty Hawk. My job was to keep grass cut, deal with diamondbacks, and try to stop waves and water taking away land. We built cabins out of abandoned bridge trestles and telephone poles. I have built seawalls and seen these cabins moved by waves from hurricanes (They’re tough.) I can see in my mind exactly where 1 meter, 39 inches, of sea level rise will sit.

Figure 2: Cypress Knees on the shore of the Neuse River after Hurricane Floyd, 1999.

If I were standing next to the Neuse River talking to a neighbor, I would say that with the evidence and knowledge I have, that a 1 meter rise in sea level was a considered best estimate of a lot of information. If I were to conjecture, I would offer that I think that 1 meter is more likely an underestimate than an exaggeration. And as for the proposed law, I would think of previous efforts to legislate the numerical value of pi, and the people in the Dust Bowl trying to sell the idea that all of the scientific information was part of a fraud trying to advance some cultural agenda. I would dismiss the proposed law as an attempt to legislate away that which stands in the way of our desires to consume and build for our personal imperatives. I would dismiss it as politics and note the names of the un-serious politicians for the next election.


P.S. My last blog was reproduced at this site with the question posed to the reader:

“Is Rood being intentionally deceptive, or is he just not very bright?”

Now in my defense, I have stated a number of times over the years that I am not so smart (here for instance); hence, that question should be easy to answer. I always felt growing up that the only time I was the smartest in the room was when I was alone. So if you decide to answer that question, then the extended answer might use Form of Argument: Adventures in Rhetoric as a hint.

Just having fun,


Figure 3: Dinosaur sculpture in Boise City, OK – taken June 2005 on the road.

Climate Impacts and Risks Climate Change

Updated: 9:54 PM GMT on July 08, 2015


Heads and Tails: Still thinking about Spring 2012

By: RickyRood, 5:45 AM GMT on June 02, 2012

Heads and Tails: Still thinking about Spring 2012

In March 2012 I planted potatoes in Colorado and it was 85 degrees F. A couple of weeks ago I put out some basil, and it frosted. As I said in the last blog, following the March heat wave I watched with interest the caster that has weather events and earthquakes on the WU homepage. There was a period of time when there were record highs and, a couple of hundred miles away, record lows.

In my blog Just Temperature, I highlighted several measures and displays of temperature information that made a consistent picture of a warming planet. If I count correctly, we are now at the 327th consecutive month that has been above the 20th century average. That average includes the 1930s, a notoriously warm decade, and it includes all of those warm months since 1985. So that average is by its definition, a high number compared with say, the 1800s. This march of warmer that average months is, by itself, pretty compelling.

In that blog, I also revisited the nice plot adapted from a 2009 paper by Jerry Meehl and a host of other authors. (Original Paper, Paper Discussion from NCAR ) It is reproduced here. This figure shows, for the U.S., the number of new record highs divided by the number of record lows – the ratio of highs to lows. In a simplistic, intuitive way, if the average temperature where staying the same, then one would expect the number of new record highs and the number of new record lows to be about the same. What is seen in the figure is as we go from the 1980s to the 1990s to the 2000s, there is trend of record highs out numbering record lows by a factor of 2 to 1.

Figure 1: Adapted from Meehl et al. (2009) the ratio of U.S. record highs and record lows by decade.

So let’s return to that WU caster information. I wondered about what sort of message I was getting from these little nuggets of information. If I picked a few days from the caster, I counted about as many highs and lows. The folks at Climate Central have developed and published a record temperature tracker. It packs in a lot of information. If you look at the daily maps, then you see the waves of warm records and cold records moving across the continent. I can see the hot days in March when I planted potatoes and the cold days in May when I planted basil. But if you take May as a whole, there were 3,188 daily high records compared with 421 daily lows. If I calculate my ratio, that is more than 7 times as many highs as lows. And that was for May, a month when my impression from the WU caster information and my basil it was relatively cool.

So what about March, when everyone knew it was hot? There were 7,755 records highs and 287 record lows, a ratio of more than 27. The temperature tracker also pulls together information about warm nights and cool days. For a variety of reasons warm nights are of special interest. From a climate scientist’s point of view, warm nights are often associated with the greenhouse effect, primarily due to water vapor and clouds. It doesn’t take a very thick cirrus cloud to maintain warm nighttime temperatures. Or, if it is simply high humidity, then it stays warm. So if the amount of water vapor in the atmosphere is increasing because it is getting warmer, then the nighttime temperature should remain high. Therefore, we might expect a trend in increasing nighttime temperatures to be a robust measure of warming. This gets confusing, because it is the daily lows getting higher. If we look at the number of warmest nighttime low records in March 2012, the number was 7,517. There were only 603 records set for coolest daily high. (What does the extra water do about the daytime highs?)

We see here a very warm spring. It’s also been very dry, but I will leave that until a later. (I know I should write shorter, more frequent articles to maintain the excitement amongst my readers.)

The Climate Central record temperature tracker is based on data at the National Climatic Data Center. They keep a nice records table, which also has easy comparisons to last year. If you look at the ratio of January through May of records maximum to record minimums for 2011 and 2012, it shows what an extraordinary year we have had so far. This year the ratio of highs to lows is nearly 12 compared with 1.7 in 2011. The 2011 number is far more similar than 2012 to the information in Figure 1 - still a pretty strong imbalance between highs and lows.

So I want to end this blog with a party trick. We have had 327 months in a row above the average temperature of the 20th century. If we played the game that there was a 50% chance of each month being above (heads) or below (tails) average, we have now rolled heads 327 times in a row. How likely is that? I think that is one half raised to 327th power, which is about 1 chance in a number that is 1 with 98 zeros after it. That makes buying a mega lotto ticket look like a solid investment. We live in a extraordinary spring in an extraordinary times. After a rocky start, my potatoes look pretty good.

Climate Change


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Dr. Ricky Rood's Climate Change Blog

About RickyRood

I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

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Clouds in the lee of the Rockies at sunset.
Clouds in the lee of the Rockies at sunset.
Clouds in the lee of the Rockies at sunset.
Clouds in the lee of the Rockies at sunset.