Turning Up The Heat: How A Warming Planet Leads to More Extreme Weather

With the recent climate talks at the G20 summit, I think many people were reminded about the climate change situation we are facing as a planet. Since this is an issue that has a lot of political, economical, scientific, and ethical factors that make it complicated, I want to just take a step back and have a look at some of the science, what scientists know, and how they understand how different pieces of the puzzle fit together. So, why should we expect that a warming planet should have more extreme weather events?

First, let’s look at two effects of global warming that seem almost contradictory: increased rainfall, and increased droughts. As the global temperature rises, sea ice and glaciers tend to melt, thus, the oceans can then absorb more heat, since water absorbs more light than ice does (this is because ice is actually really good at reflecting light). Since the ocean water absorbs more heat, more of it evaporates into the air. Additionally, because the air is warmer, water evaporates more easily, and the warm air is also able to hold more water. This leads to areas near large bodies of water, which would already be getting moderate amounts of rainfall, getting even more rain. Thus, global warming can cause places that already get rain to be more likely to have large storms.

However, global warming not only causes more extreme rain, but in places where there is not much rain to begin with, it can lead to more severe droughts. This is because in places where there may not be a large body of water which can form clouds, the evaporation that occurs is mostly of the water in the ground, which then dries up faster than normal. Thus, when there isn’t rain, plants and animals are more severely affected, since any water in the ground will evaporate away quickly and not be replaced. Thus, the increased heat will lead to places that did not get much rain to begin with becoming dryer. This naturally leads to the increase in forest fires, since plants are drier and can catch on fire more easily.

Interestingly, both the increase in precipitation and in droughts can lead to an increase in flooding. The increase in rain and snow leading to increased flooding makes sense, but why should droughts lead to increased flooding? The cause lies in the dry ground from droughts. During a drought, since there is little water, the ground dries up, and tends to harden, since the water normally helps to loosen up the dirt. Then, since the surface of the ground is harder, the surface provides a kind of barrier between any rain and the dry ground underneath. So, when it does rain, any water that falls will take longer to soak into the ground, and thus will accumulate on the surface, and since the water will then build up, it is more likely to result in flooding. As the planet is warming, the planet’s glaciers and ice caps are melting, which leads to the sea level rising. Within the next 30 years, increased flooding in conjunction with the rising sea level could cause the flooding of the homes of over 300 million people, with the water level increase in the next century potentially permanently displacing over 200 million people. This is heightened by the fact that the increase in temperature and water evaporation in the oceans provides more water and energy to form hurricanes, which means that hurricanes are growing stronger, with more powerful winds, more heavy rain, and increased size, leading to greater destruction and flooding.

Somewhat counterintuitively, climate change can also lead to some colder winter events. Understanding this effect is important, because it is a fairly common argument by those who reject the existence of climate change that since we still see a lot of extremely cold events, climate change can’t be real. However, let’s look at the science. Every year, during the fall, a westward flowing wind forms near the North Pole called the Polar Vortex. The increased temperature and amount of water in the air can disturb the Polar Vortex, causing it to “wobble”. This wobble can cause the Polar Vortex to reach further south than it normally does, causing random extreme cold snaps and snow storms in some areas. However, it is important to note that the occurrence of these occasional snow storms does not mean that global warming is not happening. On average, temperatures are increasing, and winters are warmer than they used to be, but during winter, we expect, and are seeing, occasional extreme cold events that are caused by global warming.

What was outlined above is just a description of the mechanisms behind just a couple of the effects of global warming. As the planet continues to heat, we can expect these effects, as well as many others, to continue to get more severe. From the acidification of the oceans and the mass extinction of species to the severe storms that are now increasing in frequency, many of the factors leading to these can be traced back to humans. We are reaching the point where, unlike previous generations who may have been told that the effects of climate change will only be in the future, we are seeing the effects now–and if this does not improve, then our generation will be (and already is) suffering the consequences. This is not a future problem; this is a problem that affects us right now. There won’t be a particular action that we can all take which will not inconvenience us; we can’t expect to save the planet and still continue with the modern cycle of life. So if we are to make progress towards what will ultimately save millions of lives, we need to do several things: first, recognize the scope and severity of the problem, second, realize that the solutions we come up with won’t be easy, and third, keep moving forward together to try to solve this crisis.