What happened to our climate models? (Part 2)

By Miles Evans



Everything failed, but it’s okay.  I found out last week that a small error, committed in the very beginning of the summer, has caused my main experiment to not produce any results.

It was a very small distinction that caused all of my problems.  My climate model needed to be running in a mode that allows it to compute complex atmospheric chemistry and physical interactions, but it was not.  Usually, the default is to have the model in this mode, but the particular setup I used appears to be an exception.  This problem caused my test and my control runs to produce the same exact output and so no useable data.

Looking back on the summer, it would have been wise to perform some diagnostics on my model output data early and actively look for problems like this.  The skills and knowledge to know what diagnostics to do and how to do them come with experience and I have now compiled a mental list of a number of steps to take to ensure that I don’t make the same mistakes again.

Because of this setback, the focus of my summer research has changed course.  Because my models produced valid output, I can still use that data.  Fortunately, one of the other undergraduates here ran a model that is almost exactly the same as the control model I ran, but using an older version of the model.  Now, my final summer poster will be focused on comparing the older and newer versions and discussing the improvements that were made.

In the end, not all is lost.  I am still going to have a poster to present at the symposium on Wednesday with some interesting content.  Most importantly, I think, was the amount I learned this summer and the experience I gained in this field.  Certainly, future climate modeling endeavors of mine will proceed much more smoothly, now that I know what to look for and can operate a little bit more autonomously.


Coming to a close: What happened to our simulated climate? (Part 1)

By Jake Stevens

My experience with DURI and climate modeling with Dr. Huber and the PCCRC is quickly coming to a close. After a preliminary poster printing session Monday, one last meeting with Dr. Huber Tuesday, some final revisions, and a poster presentation on Wednesday, my time will be at end. I would like to thank Dr. Huber, Paul, and the other interns, Miles and Kehao, for their help and time throughout this internship.


Map of the U.S. population in 1850.

My two models, the control and the test case, have generated output for up to 2082 and 2062, respectively. That is 124 years of climate simulated, which represents about 430 hours, or 18 straight days, of run time on Hansen, the cluster I used to run my models. The amount of computational resources necessary for this kind of research is staggering, as is the amount of data generated; it was an eye-opening experience the first time I quickly filled up my 1000GB (1TB, or double a mid-end laptop’s entire storage capacity) quota. To put this in to perspective, 1000GB of data would be equivalent to roughly 256,000 songs.

Unfortunately, it seems like my 1850 land use scenario seems to have no statistically significant influence on global aspects of climate such as surface temperature and total precipitation (though due to time and complexity constraints, the biochemical processes present in plant life, namely photosynthesis, had not been considered in the model). Still, changing the landscape resulted in statistically significant decreases in albedo – or reflection coefficient – which is exactly what one would expect from an increase in trees, so it was pretty cool to see the changes I made in the land use data set accurately reflected in my model’s output.

Overall, my internship with the PCCRC has been interesting. I got to work with Purdue’s highly ranked super computer clusters, which is pretty cool for a computer geek. I also learned a lot more about a field in which I had very little experience. I think the part that I will miss the most is the time between group meetings with Dr. Huber, Miles, and Kehao and DURI Brown Bag Lunches because Dr. Huber would tell us stories about academia, his field, and fun personal anecdotes about his work experiences.

Country roads and highways inspire Jake’s research

Credit: University of Missouri

Credit: University of Missouri

By Jake Stevens

It’s been over a month since I’ve started my internship with Dr. Huber and the PCCRC.  The first couple weeks were almost overwhelming. As a computer engineering major, I had zero experience with climate modeling or even any climate science in general. Because of this, it took some time before I began working on my own research; I spent time trying to figure out the basics.

Soon, Dr. Huber asked us to decide what we personally would like to work on.  I was at a loss for a while.  Then, I started to think about my rides to and from Purdue down I-65, through many farms and fields, and about the massive changes humans have made to the natural environment for food, space, and materials.  And so I formulated my experiment: I would investigate the effects of land use change on the climate.

To do so, I first ran a default model provided by the National Center for Atmospheric Research (NCAR) that simulates what the climate will be like if the population and carbon emissions continue as at present, with output starting at 2010. The output of this simulation will act as my control case; the land usage is formulated as usual, with no changes. This will be compared to the output of a second, modified version of the default model.  The modified version will change the post-2010 landscape to 1850 conditions. In this way, I can examine the effects that land usage has had on the climate through the change in climate that would occur if the vast majority of current farms and development were returned to their pre-Industrial Age state. I have completed a small script to modify the dataset used by the model in order to accomplish this.

I am excited to get this version of the model running and generating output so that I can begin to analyze these effects. While I wait, I will be working with Paul and Dr. Huber in writing a paper to convey my findings, as well as to use as a basis for the final poster presentation at the end of the month.

What if everyone was vegetarian?

ImageBy Kehao Zhu

Before the internship, I had never opened the program Terminal on my laptop before, so I couldn’t imagine that we would be building the climate models in the UNIX environment and using clusters from supercomputers for computing.  Sometimes, it is a pain for the newbie like me. I am grateful to Miles, Jacob, Paul and Dr. Huber’s assistance and patience in helping me to learn and to deal with the problems I faced using the new programs. I was fascinated when Dr. Huber talked about his experiences on UNIX from decades ago and now. 

I found a specific topic for my work, finally. I have few vegetarian friends and they told me they believe being a vegetarian has impact because meat production consumes a lot of energy and being a vegetarian could slow down global warming. I found the idea to be interesting and there is some literature that discusses it. I was shocked by the fact that current meat production accounts for between 15 and 24 percent of greenhouse gas emission. Researchers ran an integrated assessment model to project scenarios of different diet options, such as vegan and some less extreme vegetarianism and generally healthier diets. Some variables they manipulated were energy demand, CO2 emission and land use. Obviously, they did not expect the whole world would dump McDonald tomorrow, so their time frame to calculate was longer. The transection was set to be between 2010 and 2030.

So, I decided to use their data and run them on a climate model to project more physical results, such as global average temperature in the next 40 years. Although my methodology is not very rigorous in testing whether changing diet will slow down global warming, at least it probably will give a rough estimation. My vegetarian friends would like to see my results. Or perhaps, I will become a vegetarian if its benefit is significant.


Kehao at one of his first coffee shop meetings. Doesn’t he look excited about climate science?

Another surprising aspect of my internship is that the group sessions are in different coffee shops around the campus while many other students and professors are working in coffee shop as well. When I asked why we have our meetings in coffee shops, Dr. Huber told me that new ideas are more likely to occur in a relax place than a boring room with noise made by air conditioner. Because I don’t drink coffee at all and never think of working in a coffee shop, I have never been to those places. So far, I am becoming more comfortable with environment in the coffee shops.

By the way, there are so many rainfalls in the past few weeks. I wonder what summer weather was like one hundred years before and what it will be like one hundreds later.

Should we throw salt from the ocean into the air? Ask Carter.


An up close view of one of Purdue’s supercomputers Carter. (Credit: Purdue University/Andrew Hancock)

Miles Evans

The world’s largest surface, the ocean, may be the answer to reversing rising temperatures and its negative effects.

After a period of lots of work, failed attempts to get the code working, research, and collaboration, I have three models running. They will continue to run almost continuously on Purdue’s supercomputer, Carter*, until the end of July, when I will analyze their output and report the results.

The first model is pretty standard and will fit in with the work of the other interns’. It will be a scenario that outlines the climate should humanity take modest carbon emission mitigation actions. The other two models are my individual work and go together. One of the remaining models is a control scenario that will predict what the climate will be like in the future if we, as a species, take little action to mitigate emissions or their impacts. The other model will test a strategy for lowering the temperature of the earth by kicking a lot of salt from seawater into the atmosphere. Because the salt in aerosol form reflects light, it will have the effect of scattering sunlight back into space before it can warm the planet. In addition, it will seed clouds and hopefully make the Earth even more reflective. At least, this is the idea currently.

Strategies to lower the temperature of the Earth without controlling carbon emissions are generally called geoengineering strategies. Many of these strategies can be relatively mundane, such making all roofs white, while others are more exotic, such as floating big, reflective mirrors in the upper atmosphere or firing clouds of dust into orbit to block sunlight. Even within the category of increasing the amount of aerosols (like sea salt) in the atmosphere, there is much variety. Most commonly, people are looking at mimicking volcanoes by injecting aerosols of sulphur compounds into the stratosphere. Others look at injecting salt directly into the stratosphere by means of a system of boats, balloons, and pumps.

My model involves a simpler scenario where we use boats or rafts to spray sea water around on the surface of the ocean. While being easier to do, much of the salt aerosol that gets produced will fall to the ocean or be caught by rain very quickly. Only a very small percentage of it will complete the journey to the stratosphere, where it will do the most good. It will be interesting to see if this geoengineering strategy will have much of an impact.

*Speaking of supercomputers, Purdue and Indiana University’s rivalry has found another way to manifest itself. Earlier this summer, IU unveiled the fastest supercomputer only to be put to shame two months later by Purdue.

Meet our grad student Paul!


Paula Acosta, our first-year graduate student from southern California, will train our interns on scientific methodology and climate science, focusing on modeling.  Paul wanted to get into the teaching side of things and at the suggestion of our director, Dr. Matt Huber, he did just that.

Because he grew up near the coast, Paul became interested in climate science and how it affects the Earth. He’s ready to mentor and continue his academic career with the Center in an effort to communicate the complex problems of climate change to the general population.

“I believe scientists in general have the desire to help the environment, society, or scientific progress and climate change is that topic for me,” Paul wrote. “It allows me to utilize my degree; the problems it presents are challenging and has adverse effect on society, and the environment.”

Meet our interns, pt. 3

Meet our final intern, Miles. Up next: The grad student.

Miles Evans

Miles Evans is a rising junior, hailing from Bloomington, Ind. (Good thing he came to the right side.) Miles majors in environmental and ecological engineering, which led him to an internship with the Center. He’s undecided of his project for the summer, but says it will most likely include testing a possible global warming mitigation strategy, such as changing the albedo, or reflectivity, of large areas of the globe through various means.

“Humans have a negative impact on the environment and a lot of effort is being put into figuring out the extent of that impact.  I would like to research the effects of something positive we humans can do to mitigate the damage that we cause that may not have been fully fleshed out in the past,” Miles wrote.

He’s excited to be using the specific types of climate change models this summer because they provide an intersection of various areas that will provide a more detailed result that can be analyzed for the effects of each action.

His major specifically looks at how human engineering can affect the environment and its ecosystems. In combination with his research this summer, he hopes to look deeper into the effects and how natural emissions compare with those of man-made products.

“As a permanent resident of “spaceship Earth,” I, like everyone, am invested in the health and well-being of the Earth System.  It is my hope that modeling efforts, like ours, will serve to educate people and inform decisions on a governmental and global scale to a greater extent than at the present.”