The podcast of the University of Colorado Consortium for Climate Change and Health
Episode 1: Climate Science 101, Part 1
Jake and Cam sit down with Dr. Kris Karnauskas to get a crash course in climate science, which will be divided up into three episodes.
Dr. Karnauskas earned his Ph.D. in atmospheric and oceanic sciences from the University of Maryland-College Park followed by a postdoctoral fellowship in Ocean and Climate Physics at Columbia University. He is currently a fellow of the Cooperative Institute for Research in Environmental Sciences, an Associate Professor in the Department of Atmospheric and Oceanic Sciences at the University of Colorado Boulder, a member of the CU Consortium for Climate Change and Health, and a father of two kids.
We kick off this episode with a quote from legendary geophysicist Dr. Wally Broecker: “the climate system is an angry beast and we are poking it with sticks.” Dr. Karnauskas also clarifies the difference between “climate” and “weather”:
Dr. Karnauskas then explained there we have a pristine record of rising global temperatures and carbon dioxide (CO2) levels in the atmosphere, and that you really cannot dispute this with a sound head on your shoulders. Take a look:
Carbon serves as the backbone in our fossil fuels, and is released as CO2 (carbon bound to two oxygen atoms) when we burn them. Global CO2 levels have fluctuated in past glacial cycles–how can we know that the current rise is due to human activities ( i.e. burning fossil fuels)? Dr. Karnauskas explains that we can measure the “isotopic ratio” of carbon in the atmosphere and know that humans are causing the current and unprecedented rise in global CO2.
So CO2 is going up due to human activities. What’s the big deal? Well, it turns out that CO2 is a major “greenhouse gas”, or GHG. Dr. Karnauskas explains what the greenhouse gas effect is and why it contributes to an increased global temperature. There are some great visual aids out there that demonstrate the greenhouse effect–check out the animation and video below from NASA’s website.
To close out this episode, Dr. Karnauskas provides an overview of how climate models work–what their basic assumptions are, how they partition the world into a bunch of “pixels”, and how gigantic computers apply the laws of physics to each of these pixels to simulate what will happen in the future under different greenhouse gas scenarios.
Climate models partition the world into “pixels”
These models can then estimate future temperatures for different emissions scenarios, as displayed in this figure from the recent IPCC report.
background readings and resources for the interested listener: