How Does Global Warming Work?
The earth, which includes land masses and mountains and cities and oceans, is surrounded by a layer of gases which we call the atmosphere. There are many different types of gases in the atmosphere, including oxygen, nitrogen, carbon dioxide, and hundreds more. This atmosphere is incredibly important. First of all, it gives us oxygen to breathe and protects us from cosmic radiation and meteorites. When the rays from the sun reach Earth, some of its gases also trap the rays’ heat and keep the atmosphere warm, allowing us to go outside without freezing even on cloudy days or during the night. This set of gases that trap heat and keep the earth warm are called “greenhouse gases” (GHGs) because they act like a glass greenhouse with plants in it. There are many of these gases in the atmosphere; the most important and prevalent ones are carbon dioxide (CO2) and methane (CH4) — and even though they are just a small percentage of the atmosphere, they are largely what keeps the earth from freezing and allows us to live on it.
However, the concentration of greenhouse gases in the atmosphere has been increasing since the beginning of the Industrial Revolution in 1870. That’s when people discovered fossil fuels, such as coal, oil, and natural gas, and started burning them to create energy for power plants and more. Burning these fossil fuels does more than just create energy. It also releases carbon dioxide and other greenhouse gases into the atmosphere (these released gases are called “carbon emissions”). Those carbon emissions have drastically increased the atmospheric concentration of CO2 since the beginning of the Industrial Revolution. In 1870, CO2 levels were approximately 270 parts per million (ppm), but as of 2016 they are over 400 ppm. This has also led to a certain amount of “global warming”: the average global temperature has increased by about 1°C (1.8°F) since 1870. It may not seem like a lot, but it has massive global consequences.
CO2 concentrations are still rising, and the temperature is rising with them. Humans continue to burn fossil fuels and spew greenhouse gases into the atmosphere, and the rate of carbon emissions has continued to grow over the years. Other things are also helping to increase these emissions and global temperatures. For example, trees and forests suck CO2 out of the atmosphere in order to grow, but deforestation has taken away those forests and their ability to “sequester” carbon. Cows raised for beef and dairy burp up loads of methane, which is a much more potent greenhouse gas than CO2. Some “natural feedbacks” are releasing more GHGs as the earth warms. For example, there are more forest fires, which release CO2 from burning forests, and then more warming causes more forest fires, which release more CO2, and so on. Frozen methane at the bottom of the oceans is starting to melt and release gases into the atmosphere, and so on and so on. These may also have locked in a certain amount of warming far into the future, no matter how much we reduce our emissions now.
This warming has many climate-related and other consequences. Direct climate consequences include things such as hotter, longer, and more severe heat waves; stronger and more frequent storms; longer and deeper droughts; more frequent forest fires; stresses to natural environments and ecosystems; and sea level rise flooding coasts and islands worldwide. These climate consequences will impact humanity in a number of ways. For example, there will be infrastructure damage from storms, flooding, and fires; more deaths from extreme weather and heat waves; migration away from flooding coasts, droughts, and more; and political and economic tensions from all of these. It will take many partnerships and much collaboration to protect nature and people into this changing future.
Scientists are predicting that temperatures will continue to rise in the coming decades, potentially by several degrees Celsius. Natural feedbacks and growing “feedback loops” will also contribute to warming, although this is largely ignored by activists and politicians alike. Nobody can say for certain how much temperatures are going to rise, but nearly everybody agrees that a lot depends on how many more emissions we put out. Global leaders are continuing to put effort and money into renewable energy and other low-carbon development around the world. This will absolutely help with global temperatures, and severe emissions cuts may even make several degrees of difference. There has also been a global call to keep warming below a 2°C increase since pre-industrial levels, which policymakers have said is the limit before we experience the “worst impacts” of climate change. The call has spread worldwide and is echoed in nearly every speech, interview, and article that comes out about climate change. It’s largely framed as the point of no return and the stark cut off between stability and catastrophe.
However, there is a catch to that idea that may lead to widespread problems. The whole 2°C argument lays out the vision that staying below that one number is enough to save humanity. For example, some activists might say that “this island will be underwater unless we stay below 2°C,” or they say the same thing for drought or any other impact. In reality, though, each hundredth of a degree has one extra bit of impact. That means that some islands may still be underwater at 1.9°C, or even 1.1°C, as opposed to the 2°C figure saving everything around us. It may ultimately be impossible to reach that goal at all; with the combination of the nature of society, the yet-unaddressed feedback loops, and many other factors, we may overshoot it no matter how much we try. This all means that we will have more storms and heat waves, sea level rise and flooding, food shortages and mass migration, and more. It is absolutely a scary future, but we need to accept it and start getting ready in order to protect ourselves and those around us.
The NED team believes that it is not possible to stay below 2°C, and that we must prepare for more–and we must realize that every extra piece of preparation will have one more piece of positive impact. We can also focus our efforts on protecting the people that need it most, which is a powerful form of climate justice. This is especially powerful for people with disabilities, who need support and specialized adaptation to stay safe in the future of climate change. Please, reach out and join us in our efforts to justly adapt to climate change, for our future and the future of those around us by contacting Alex Ghenis at firstname.lastname@example.org.
- National Resources Defense Council (NRDC): Global Warming 101
- The Royal Society: Basics of Climate Change
- Climate Change 101 with Bill Nye (YouTube)
- Wikipedia on Climate Change
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