Six Degrees - Four Degrees of Warming

In this chapter of Six Degrees, Lynas focuses on the affects of a global temperature rise of four degrees Celsius. These include sea level rise due to melting ice sheets and the substantial flooding the displaced peoples this would cause, loss of crop production due to warmer temperatures and the foods shortages related to this, increased drought and heatwaves, the destruction of soil due to desertification and increased precipitation as rainfall rather than snowfall due to higher temperatures, and carbon released into the atmosphere through the melting of permafrost, causing a positive feedback loop contributing further to climate change.

The five main points of this chapter are as follows.

Flooding in New Orleans after Hurricane Katrina.

1. The Antarctic Ice Sheets are vulnerable to collapse which would cause a dramatic rise in sea level. The West Ice Sheet is anchored below sea level, and warming could cause total collapse of this ice sheet, which would quickly overwhelm the world's coastlines. The East Ice Sheet contains enough ice to raise sea levels by 50 meters (approximately 165 feet), making the coastlines unrecognizable. Sea levels are predicted to rise at least half a meter (or one and a half feet) through four degrees of warming. Lynas uses the coastal city of Alexandria as a jumping off point, describing that 1.5 million people would be displaced and $35 billion would have to be spent on repairs to just this one city. Places like Bangladesh, Boston, New Jersey, and Shanghai would all be at risk for major flooding and displaced peoples. New York, London, Venice, and other large cities would have to build fortification against flooding, but as we've seen from New Orleans, these do not always work and require huge amounts of money.

2. Agricultural breadbaskets all over the world will be unable to produce a sufficient amount of food. Lynas points to China to illustrate this, projecting that staple crops like rice and corn will drop in production by 40% due to a decrease in river water and an increase in desertification. Western North America, southern Africa, and western South America will face similar problems under a four degree warming. Increased rainfall in the winters will lead to destruction of top soil, which will compound this issue even further.

3. Heatwaves will increase, leading to human casualty and a drastic change in many ecosystems. Large parts of Spain, Portugal, France, Italy, Greece, and Turkey will experience an increase in dangerously hot days, similar to the 2003 heat wave in Europe that killed more 70,000 people. Additionally, Switzerland will have an increase in wildfires and droughts.

4. Weather will change all over the world. The Alps will experience a climate similar to North Africa, with less snowfall and increased glacial melt, causing drought. Snowfall will decrease all over Russia, and as precipitation will come in the form of rain, this will cause major flooding all over the country. Super storms will increase in places like Scotland and Germany, causing damage costs and forcing relocation for millions of people.

5. Melting permafrost and ice will increase the amount of carbon in the atmosphere. As ice melts in the Arctic, Siberia, Alaska, Canada, and Greenland, it not only causes the destruction of infrastructure and the population decrease of animals, but also releases the approximately 500 billion tons of carbon that is currently permanently frozen underneath. This creates a positive feedback loop, as the increase in greenhouse gases from this melting will only increase the rate of melting and release more greenhouse gases.

Lynas proposes that the changes brought about by four degree warming will likely inevitably lead to five degree warming, which in turn may lead to six degrees all by itself.

That's all for now.

Write to you later.

Danielle K.