# Strength in Numbers: Mathematicians Unite to Tackle Climate Change and Other Planetary Problems

- March 21, 2013
- Evelyn Lamb
- SCIENTIFIC AMERICAN
- http://www.scientificamerican.com/article.cfm?id=mathematicians-unite-to-tackle-climate-change-and-other-planetary-problems

2013 is the year of "Mathematics of Planet Earth" for hundreds of organizations around the world

What do polar ice caps, guinea worm disease and wildfires have in common? All are being modeled with cutting-edge mathematics. Mathematical societies and institutes around the world are participating in "Mathematics of Planet Earth," or MPE, this year. They aim to study the math that underpins geologic and biological processes on our planet as well as encourage more math researchers to tackle these problems. Events are planned for the year 2013, but the organizers hope that the initiative will have lasting effects.

MPE is the brainchild of Christiane Rousseau, past president of the Canadian Mathematical Society. She had the idea several years ago of uniting mathematicians from across the globe to study problems ranging from climate change and sustainability to earthquake prediction and disease pandemics. It was a lofty goal but it resonated within the community and took off. Just one week elapsed, she says, from the time she conceived the notion to when “all the North American research institutes” came onboard. Enthusiasm spread from North America overseas, and now MPE partners include societies all over the world, including schools and centers in Europe, Latin America, Southeast Asia and Africa.

A satellite view of Earth. Mathematicians across the globe are devoting 2013 to studying the mathematics behind a wide range of processes on our planet.Image: NOAA/NASA/GOES Project

Climate change is the poster child for MPE. Mathematicians routinely travel to Antarctica to study polar ice; they are working on figuring out how quickly Earth is warming, what crops will be most affected by climate change and where the tipping points are if we want to try to mitigate damage. But even before questions of the climate and sustainability became paramount, Rousseau says, mathematics was, and still is, vital for discovering many aspects of the planet itself: Ancient scientists determined that the world was a sphere by observing the angle of the sun at different points on the planet. In the 1930s Danish seismologist Inge Lehmann used mathematics to determine that Earth is not molten liquid throughout, but has a solid core. "You cannot see what's inside the Earth with your eyes," Rousseau says. "I like to tell students, 'you put your mathematical glasses on, and then you understand.'"

Some mathematicians themselves don't realize that all of this modeling actually uses novel techniques. Barry Cipra, a freelance mathematics writer, says, "Within the mathematics community there can be the view that these are differential equations that were worked out hundreds of years ago," but in reality the models aren't all "off-the-shelf." Real ingenuity and new ideas are needed to develop them. One goal of MPE is to convince more mathematicians that climate change and other planetary problems are not only important but also interesting. "That's what the mathematicians like when they choose a problem," Rousseau says.

Other goals of the MPE initiative are increasing public understanding of the mathematics behind climate change and other planetary problems as well as using these real-world questions to excite students about math starting as early as elementary school. In addition to preparing educational materials for schools, partner organizations are offering public lectures about all sorts of topics related to the mathematics of the planet—and its residents—from global warming to crime patterns.

MPE itself is only a framework. It has a Web site with information about related events and a daily blog written by volunteers. But partner organizations such as the **Mathematical Sciences Research Institute (MSRI) **and the Simons Foundation host and sponsor the lectures, courses and exhibitions held in conjunction with the initiative. "We have no budget—the partners have a budget," Rousseau says. [The MPE2013 Simons Public Lecture series is fully funded by the Simons Foundation and those lectures that are hosted by the MPE2013 partner organizations around the world are made possible through the generosity of the Simons Foundation.]

The initiative officially launched in Canada on December 7, 2012, and in the U.S. on January 9, 2013 at the Joint Mathematics Meetings in San Diego. Other countries have had inaugural events since then. The European launch was held March 5 in conjunction with MPE day at UNESCO headquarters in Paris. Events that day included a screening of the film Exit (about human global migration), a panel discussion on what mathematics can do for the planet and a public lecture by Edward Lungu of the University of Botswana on utilizing the environment to manage HIV/AIDS.

Rousseau hopes that the initiative will help nurture new ideas for dealing with climate change and encourage changes at the political level. Rousseau says that communicating the economics of the situation to politicians is key. "They want to know how much it will cost if you act now, and how much it will cost if you don't act now. It will be so much more expensive if we act later."