“Most people would never ignore the advice of 97 doctors in favor of three.”
A friend of mine landed in Istanbul last week, escaping +50C in Dubai. There wasn’t much relief here for him, as temperatures hit an all-time high of 49,5 degrees. Despite weather irregularities becoming more frequent, I still have to prove time and time again that a) climate change is real and b) it is man-made. Now I think that I’ll just give people one book, that takes about an hour to read, and that clearly explains “What we know about climate change”, as its title goes. Or in case someone can’t be bothered - just give them the link to this article, where I’ll sum up the keynotes from it.
Mr. Emanuel first lays down the basics of climate change physics. The key to climate change is in the air. Literally. Pure air, that is a molecule of atoms of oxygen and nitrogen, barely interacts with solar radiation beaming down on Earth and with Earth’s radiation, beaming to outer space. If we had just pure air, the average surface temperature of Earth would be about -18C (0F), but in fact, it is about 15,5C (60F).
What heats Earth up, are the molecules of water, carbon dioxide, and methane (there are of course others, but these three are responsible for the bulk of the heating). All of them absorb and emit radiation (i.e. heat) much better than pure air. These gases in the air create what is known as the greenhouse effect - they absorb heat and radiate it back down to Earth as well as to outer space.
It wouldn’t matter much if CO2 and methane would disappear from the air as fast as water (which only stays for about 2 weeks). Now a molecule of CO2 can stay in the air for over 100 years, and after that, 20% of CO2 may remain in the air for up to 1000 years. Methane stays up a bit less, but it catches heat 80 times better than CO2 in the first 20 years and 40 times better in the next 100 years.
What’s important, is that it doesn’t take many GHGs (greenhouse gases) in the air to cause the planet's surface to warm up. Water vapors never make up more than 3% of air. CO2 is currently at 421 molecules per 1 million molecules of air (called parts per million - ppm). At the time of writing the book, it was 395 ppm. At the beginning of the Industrial Revolution - 280 ppm. A 6% increase in a few years, and a 50% increase in the last three hundred years.
So, the GHGs get into the air, stay there, and heat up the planet. That sorts out the physics of it. Now, this growth, which was especially rapid in the last 30 years, cannot be explained by any natural phenomena. No volcanic eruptions, no shiftings of the Earth's axis, nothing can explain this growth. That leaves human action as the only plausible cause of global warming. And this is the consensus of 97% of all climate scientists on the planet.
Would you follow the advice of 97 doctors for your health, or just the 3 who happen to have a different opinion? Well, that was exactly what a lot of people have been doing for the last 50 years. We’ve seen that before. Public campaigns supporting cigarette smoking have delayed public response for 30 years, despite the existence of clear scientific evidence linking smoking to cancer. Global health costs of coal mining are estimated the range from $65 to $185 billion, bringing it close to global health costs of fighting lung cancer just in the US ($190Bn in 2015).
Health costs alone should have been enough to make people and policymakers wonder. However, the risks of climate change are much greater. Despite all that we know about climate change, it is hard to predict its exact consequences. The system for absorbing and releasing heat in the air is chaotic. Mr. Emanuel points out that the problem of climate change is a problem of global risk management. He singles out four risks.
The first is floods. Three feet (91cm) rise in sea level will displace 100 million people and affect 11 out of 15 largest cities on earth. If you think that will not happen fast, then rest in comfort knowing that sea levels have already risen by four inches (10 cm) in the last 60 years.
Hurricanes are second. In the North Atlantic, their power output doubled since the 1970s. The authors’ own research shows that hurricanes respond to warming earth faster than originally expected.
The third is drought. Droughts could become more frequent and hit fertile areas, resulting in failed harvests and food shortages. As these are likely to happen in the Middle East, it could lead to political unrest and another refugee crisis.
The fourth and final risk is ocean acidification. While it doesn’t sound as apocalyptic as the previous three, it is a serious matter for two reasons. First, higher levels of acidification make it difficult for a wide variety of marine organisms to form calcium carbonate shells (more on that in another book that I’ve recently read, with a slightly spirited title “The 6th Extinction”). Many of these creatures form a base in the food chain, and we run risks of additional extinctions and troubles with food from the sea. Second, higher acidity means that the ocean is less capable of absorbing CO2, meaning that more of it stays in the atmosphere and causes further warming.
If I would be asked, what books could I recommend on the subject of climate change, Kerry Emanuel’s “What we know about climate change” would top the list. You can read it in under an hour, but it will set you up with all the necessary knowledge about climate change science, evidence of human-caused warming, and highlights of key risks. While the book is thin on what should be done, I hope that the next book that I am about to read - “How to avoid the climate disaster” by Bill Gates, will shed some light on it.