by Pro­fessor Kenneth Hayes

We are in a moment of awak­ening about the climate crisis. As of today, there are 334 towns con­taining a total pop­u­lation of 33 million people that have passed a climate emer­gency dec­la­ration. Most of these dec­la­ra­tions have been passed since the Inter­gov­ern­mental Panel on Climate Change issued a stern report in October 2018 sum­ma­rizing the dif­ference in climate impacts between an increase in Earth’s average surface tem­per­ature of 1.5 Celsius versus 2.0 Celsius rel­ative to the average surface tem­per­ature at the start of the indus­trial rev­o­lution. The warming trend over the past several decades is very clear: On our current tra­jectory Earth’s tem­per­ature will cross 1.5 C warming around 2040 and 2.0 C warming around 2060. The con­se­quences to humans and other life on the planet of 2.0 C warming are severe.

The first three Mondays in Feb­ruary, I pre­sented three lec­tures on climate change. The first lecture was on the physics that deter­mines the average surface tem­per­ature of planets with and without atmos­pheres. The physics that deter­mines the tem­per­ature of planets without atmos­pheres is very simple: a one-line formula cor­rectly pre­dicts the average tem­per­ature of planets and moons in the solar system that lack atmos­pheres. The atmos­pheric green­house effect increases the average surface tem­per­ature of planets that have green­house gases in their atmos­phere. Cur­rently, the green­house effect on Earth increases the average planet surface tem­per­ature by 33 C (60 F) from what it would be if there was no atmos­phere, and this is why the oceans are not frozen. The second lecture pre­sented some of the con­se­quences of the global warming occurring on Earth due to our emis­sions of green­house gases pro­duced pri­marily by the burning of fossil fuels. Our emis­sions have increased the con­cen­tration of carbon dioxide in the atmos­phere by 46 percent since the start of the indus­trial rev­o­lution. The third lecture dis­cussed pos­sible solu­tions.

The climate problem is very well under­stood. Cur­rently there are a large set of solu­tions to the problem that could be imple­mented. The essential chal­lenge is getting people to act. Trag­i­cally, there is a vast amount of dis­in­for­mation in the media and on the Internet about the climate issue. The people who have the most to lose by a con­version of the world’s energy systems from fossil fuels to renewable energy under­stand that the most effective way of slowing this con­version is to spread doubt about the science and the con­se­quences of global warming. One of the main goals of my three lec­tures was to provide enough knowledge of the physics — including a demon­stration of the striking effec­tiveness of carbon dioxide to trap infrared radi­ation — so that anyone who fol­lowed the lec­tures would under­stand what is going on and would thus be insu­lated from the massive amount of dis­in­for­mation on the climate issue.

The most important things you can do to work towards a solution are to educate yourself and talk to others about the climate problem. Vote for politi­cians who under­stand the problem and who are com­mitted to working towards a solution. Learn about your carbon foot­print, and take action to reduce it. I have included in my lecture slides many links to web resources at various levels from the most intro­ductory to recently pub­lished peer-reviewed sci­en­tific papers. These links are a good place to start expanding your under­standing. If you wish to get access to the Pow­er­Point slides I pre­sented in these lec­tures, please contact me.