The Path We’re On
The IPCC has put together a graphic showing the many possible outcomes of climate change. Unfortunately, it does not communicate much unless you are already well versed in climate science.
Today we have already locked in about 1.5 degrees Celcius of warning. With a degree and a half of warming, we have started the sixth major extinction event in Earth’s history, the first in 65 million years, when the dinosaurs went extinct. We have raised the ocean’s acidity to a point where the world’s coral reefs are no longer able to survive and two-thirds of the Great Barrier Reef has died off. Large parts of North America and Europe are experiencing drought, while other parts of the globe are experiencing increasingly powerful tropical storms. Ocean levels are rising, causing displacement from some islands and low lying communities, and making flooding more likely in many coastal cities. This extreme weather is just one consequence of the warning we have already induced today, while we are still making the problem worse.
As we add more carbon to the atmosphere, as we deplete our carbon budget and rack up a greater carbon debt, the consequences become increasingly grim.
As we approach two degrees of warning, large areas of productive farmland will go fallow, leading to food insecurity. This is already happening in California’s Central Valley, the salad bowl of the United States. Water scarcity due to drought has lead to some farms turning to dust because there is not enough water to irrigate them. Some California residents have been required to cut their water usage back by up to 40%. Thankfully, for many in California, that is easily accomplished simply by letting their lawns go unwatered. It won’t be so simple when drought hits less affluent areas of the world.
By the time we hit three degrees of warming, the Greenland and West Antarctic Ice sheets will have melted. The rapid addition of fresh, cold water to the Atlantic Ocean will disrupt the circulation of water throughout the world’s oceans. It is believed that this flow of water drives the atmospheric jet stream. By disrupting the ocean currents, we will also stop the jet stream. This will have unpredictable consequences for the Earth’s ecosystem.
The cumulative effects of these impacts to the globe means that by four degrees of warming we will see mass migration and conflict. As food and water become scarce, people will start to move to places that haven’t been as hard hit by climate change. Brexit is a direct result of the ongoing European Migration Crisis, and it is not out of the realm of possibility that Italy, France, and Germany will follow the United Kingdom out of the European Union after their elections later this year. The continued existence of the European Union is in question due to the current Migration Crisis. Unfortunately, the European Migration Crisis is just a minor harbinger of the displacement we will see as the world continues to warm, and we are already seeing the fall of the liberal world order. Climate displacement will lead to affluent countries sealing their borders to foreigners and return to isolationism as a defense against in influx of climate refugees.
The climate refugee crisis will only grow as we reach five degrees of warming, when large portions of the Earth’s surface will become uninhabitable. Parts of Africa, the Middle East, India, and China are at risk of being uninhabitable. Heat waves topping 55°C (130°F) will become normal, a temperature which the human body is unable to cope. These areas are home to nearly a third of humanity. All of these people will either need to migrate to more hospitable places, or die. With five degrees of warming and isolationist policies from affluent countries, it is not unreasonable to think that the human population of Earth returns to under 6 billion people as the result of the death of billions due to climate change.
Through all of this there are risks of unforeseen events and feedback loops that may strengthen or diminish the effects of climate change. The biggest risk that can be foreseen but not quantified at this point is the melting of the Arctic permafrost. It is estimated that there are 1,400 gigatons of CO2 trapped in the Arctic permafrost that is at risk of being released in a warming world. As discussed previously, 1,400 gigatons of CO2 would raise the global temperature by three degrees. Even if humanity can stay within a carbon budget for two degrees, it may be that we end up at five degrees from runway heating due to permafrost melt. Conversely, there is some evidence that the world’s plant life is stepping up to absorb a greater amount of CO2, slowing the rate of global warming. There is a chance that unforeseen circumstances will make climate change a lot better or a lot worse that anticipated by the climate models. However, we cannot count on unanticipated feedback loops to save us from ourselves.
So we are faced with a choice, every degree matters, every gigaton of CO2 we emit will make the world worse and increase the suffering of future generations. Our choice is how much suffering are we willing to inflict on our children and grandchildren in order to maintain our current way of life. Every tenth of a degree matters in this fight, every tenth of a degree increases the burden future generations will face. We must choose to reach for a carbon free future quickly in order to provide as prosperous future for the world as possible.
[Note: This is one article in a longer series on climate change, part of a larger look at how local communities can address global issues related to climate change, housing affordability, the local economy, the fiscal solvency of cities, and public health.]
