A climate change Q&A
Series of columns sparks a phone call from a concerned grandmother
The recent Examiner articles using Karlstad, Sweden, as a model city for Peterborough’s climate-change actions, have elicited some interesting responses. The phone call discussed here was from a woman with grandchildren who was obviously concerned about the issue but had some serious questions about climate change. This summarizes her questions and my answers.
Q. How do we know how much carbon dioxide (CO2) there is in the world’s atmosphere?
A. Since 1957, CO2 levels have been measured at an observatory near the top of Mauna Loa in Hawaii, which is high enough that they are not perturbed by local sources. These measurements show that the CO2 level is continuing to increase about 2 per cent a year; that’s 20 per cent over just 10 years! Current levels are the highest in 800,000 years.
Q. But we have not been measuring CO2 for that long. How can we tell what the levels were like in the past?
A. The most direct method is to measure bubbles of air trapped in the polar ice sheets. By taking ice cores to great depths, one can track the CO2 levels year-by-year, much as the width of tree rings gives information on the climate in a given year. These measurements show that the CO2 level was quite constant at about 280 “parts per million” of air over the 10,000 years before the industrial revolution, but has risen the fastest ever over the last 150 years to over 400 parts per million now.
Q. But Canada produces only about 2 per cent of the World’s greenhouse gases. Why should we try to reduce our emissions compared to China, for example?
A. Even though it has a relatively small population, Canada was the World’s 9th largest emitter, by country, in 2015 when it produced about 2.3 times the amount of greenhouse gases per person than China, and 7.1 times as much as a person in Brazil. If our neighbour put out 7.1 times as much garbage each week as we did and was not penalized, we’d see that as unfair. Moreover, the developed countries have been the main emitters of greenhouse gases in the atmosphere for decades, so we have a moral responsibility to cut our pollution.
Q. But what can you and I do about it? We’re just two people.
A. Climate change is a global problem and requires a global response. Every country in the world has now signed onto the 2015 Paris accord, agreeing to reduce their greenhouse gas emissions by amounts each country decides is appropriate for them. The USA recently said it is opting out, but it can’t officially do so until November 2020 (after the next presidential election). The Paris accord’s goal was to keep the global temperature rise below 2 degrees when climate-change results become very serious, and hopefully below 1.5 degrees. Unfortunately, the World’s temperature has already risen about 1 degree and will rise to over 3 degrees unless countries increase their commitments made under the Paris accord.
Q. But what if China and other large countries continue to pollute?
A. All the world’s countries promised to reduce emissions under the Paris accord. China has really started to curb its greenhouse gas emissions, partly because its smog problem from coal-burning has become so serious. At Paris, China promised that its emissions would peak by 2030 and then fall. China has already surpassed its solar electricity target for 2020, and wind energy is on track to exceed its 2020 target by roughly onefourth. However, after three years of no growth in China’s CO2 emissions, they have started to rise again, so China remains a problem because of its large population.
Q. What has Canada done to reduce greenhouse gas emissions?
A. Canada has committed to reduce its emissions 30 per cent below 2005 levels by 2030. However, Canada’s emissions rose 27 per cent between 1990 and 2005. Therefore, our promise means only a three per cent cut in emissions below 1990, far inferior to Sweden’s promised 40 per cent cut by 2020. Moreover, in March 2017, Environment Canada projected almost NO reduction in emissions by 2030 under current government policies. The federal government and most provinces recently signed a PanCanadian Climate Framework that will guide emission reduction policies for the coming years. We still have a long way to go, however, although we are starting to make some progress locally. For example, see the Peterborough Examiner from Dec. 8, “Communities taking a new, greener approach”.
Alan Slavin is a retired Trent University physics professor, and is a member of the Community Climate Change Working Group of Sustainable Peterborough. He is a member of For Our Grandchildren (Peterborough).