The Earth is getting warmer. That’s a fact that essentially everyone agrees with. But what’s much more controversial is the cause. And spoiler alert: it’s us. So there’s some confusion over the terms global warming and climate change. But really, they’re the same thing. The Earth’s temperature is increasing at a much faster rate than is natural. But that doesn’t necessarily mean that all places on Earth are going to have hotter temperatures all the time. In fact, as I’ll talk about later on, some parts of the world can potentially get colder as the Earth’s temperature increases. So because of that, the term climate change is typically used instead.
Now, I’ve heard way too many people say something like “But we still have winters! The globe can’t be warming!” No. Please stop. See, weather is different from climate. But also, it’s the average temperature over the entire globe that we care about. And since 1880, that value has increased by 0.8 degrees Celsius, with two-thirds of that warming occurring since 1975. And get this, the past three decades have been successively warmer than any preceding decade since 1850. But let’s take a step back for a moment and analyze why the Earth is warming in the first place. See every day, solar energy from the sun reaches us here on Earth in the form of visible and ultraviolet light. Some of this is reflected off the Earth’s surface due to any reflective surfaces like snow and ice. And technically speaking, this is called the earth’s albedo.
But what about that light that didn’t get reflected off the Earth’s surface? Well, that warms the planet, which then releases its own infrared radiation, which is invisible to the human eye. But here’s the problem, carbon dioxide gas in the atmosphere is able to absorb some of that infrared light and re-emit it, keeping that energy from leaving the Earth. Now, for a while, greenhouse gas emissions were balanced out by the amount that was naturally absorbed. But if the amount of emissions increases, the atmosphere is able to trap more heat and raise the earth’s temperature. And that is exactly what is happening. Since pre-industrial times, the concentration of carbon dioxide has increased by 40%. In fact, in the last six decades, the amount of carbon dioxide has been on a steady rise. According to research by the Intergovernmental Panel on Climate Change, the levels of carbon dioxide, methane, and nitrous oxide are higher than they have been in the last 800 thousand years. And that extra carbon dioxide is being emitted primarily through the burning of fossil fuels. Okay, now at this point, you may be tempted to tell me that the real bad guy in all of this is water vapor. And you’re right. Doubling the amount of carbon dioxide in the atmosphere will lead to a one degree Celsius increase in temperature, whereas the presence of water vapor will increase that value to 3 degrees. But what you may not know if that water vapor levels increase because of an increase in carbon dioxide. The more CO2, the hotter it gets, allowing the air to hold more water vapor. And the more water vapor there is, the hotter it will continue to get. It’s a positive feedback loop all pointing back to carbon dioxide. So why is this such a bad thing? Well, the more the globe warms, the more intense our storms, droughts, and floods will be.
The ocean becomes more acidic as it absorbs more carbon dioxide, which is disastrous for its inhabitants. And massive ice sheets like those in Greenland and Antarctica are melting at the highest rate we’ve observed in the last 20 years. Combined, these two ice sheets are thinning at a rate of 500 cubic kilometers a year. And as you may expect, this is causing the sea-level to rise, further decreasing Earth’s albedo, which, you guessed it, also causes less light to be reflected and the Earth to warm up even more. And quite possibly the scariest consequence of the ice sheets melting is its affect on the North Atlantic drift. These are ocean currents that bring warm temperatures and nutrients to the waters off of the Eastern American coast and Western Europe. As the ice sheets of Greenland melt, the fresh water influx makes the surface water less dense. Therefore, this water doesn’t sink, and slows the currents down, which prevents the necessary heat transfer to keep the temperature of Europe from getting too cold. Now, we aren’t going to have some type of The Day After Tomorrow scenarios break out all of a sudden, but it’s important to start taking preventative measures now to ensure things don’t get even worse. I’ve included a bunch of great resources in the description of this video if you want to learn more and I encourage you to share this video with someone you know. The more educated the general public is, the more likely we are to actually make a change.