The Global Syndemic, Part Two

 The image below is hard to read, I know. But I'm going to unpack most of it in the coming posts.

 

 

 

Let's start with the simplest, most direct problem: heat itself. Excessive heat that lasts for several days kills people. It's not a major cause of death in the U.S., although it's hard to quantify because studies have found that heat is often not recorded as a cause of death on death certificates when in fact it should be. Based on death certificates the rate is generally between 2 and 4 deaths per million people per year in the U.S. But globally, the number of heatwave events is rising.

 

 

 

The consequences will be most profound, of course, in the hottest parts of the earth. Heatwaves in the Middle East, India, and elsewhere in the tropics are starting to make some places uninhabitable, which will contribute to the international migration crisis. 

Next, given the year we've just lived through, I don't have to tell you about wildfires. Wildfires are a normal occurrence, of course, and are essential to the maintenance of ecosystems where they occur. In,  fact, while the extent of wildfire in North America has been much greater recently than it has been for many decades, it may be, it may be comparable to the extent in the early 20th Century.* However, wildfires globally are happening now in places they have not happened before, and on an unprecedented scale. I haven't been able to find a concise graphic showing the extent of wildfires globally over the years -- all of the good imagery seems to pertain to the U.S. But what's most important is the burning of the Amazon -- not so much a consequence of climate change although the region is getting drier, but of intentional human activity -- and Siberia. The image below shows the burn scars in the larch forest of Sakha as of September 10 of this year, taken by NASA's Terra satellite. The 8.4 million hectares burned were the most since data collection began in 2000.

 

Fires destroyed more than 18.16m hectares of Russian forest in 2021, the most since satellite monitoring began.  Of perhaps greater concern are peat fires in what used to be Siberian permafrost. Here's an explanation of how that is happening in the region shown above. And here is a discussion of the complex issues globally. There are multiple feedback loops. There is continuing global pressure to expand the extent of agricultural land, which I will discuss next. This results in people intentionally clearing forest by burning. Climate change dries out forests and melts permafrost, causing fires in places that didn't have them in the past, and causing fires to burn down into the peat. These fires in turn release enormous amounts of carbon into the atmosphere, which accelerates climate change. This increases the extent of fires, and also eliminates some formerly cultivatable land due to water shortage, as I will also discuss. Which of course increases the pressure to clear additional land. 

* There is a graphic circulating among climate change deniers showing a much greater extent of wildfires in the 1920s than recently. The Forest Service has stated that this is bad data based on flawed record keeping systems in those years and has withdrawn it. But whatever the truth about the extent of wildfire in the Western U.S. in the past, the global situation I describe is indisputable.