Floods and climate change
Climate change is a complex subject.

Almost all predictions of how it’s expected to act are likely to be altered, if not outright discarded. One thing scientists feel they have a good handle on, though, is how climate change will impact storms globally.

It’s easy to say climate change means the planet is getting warmer, but it’s harder to understand what that means. There are a lot of changes predicted with climate change, but many of them stem from some pretty basic meteorology.

The basics

Rainstorms form when a cold air front collides with a warm air front. You may have learned about this in high school, or at least seen the indicators for it on the local weather station. When two fronts of differing humidity and densities mix, rain develops, falls to Earth and is evaporated. The amount of rain that falls and the severity of the storm depends on how much humidity is available and how different the two fronts are.

Climate change is increasing the amount of warm, humid air and decreasing the amount of cold, dry air. This means two things: Rain-producing storms will become less frequent, and the storms that do come have the potential to be more severe.

Expecting the unexpected

There are a few surprising changes that come about thanks to this fluctuation in weather patterns. Everyone is aware that sea levels are projected to rise thanks to melting sea ice, but what about flooding? That can be harder to predict. Luckily, there are rain gauges all over the world that have been tracking rainfall for years, and some for much longer. If you take out the anomalies, like when a fox urinates in the rain gauge, you end up with a pretty accurate representation of global rainfall.

Since we can accurately measure the rainfall from many different areas around the world, we can get a good grasp of how climate change is affecting rainfall. The problem is that the rainfall changes are different in various parts of the globe.

Globally, rainfall seems to be decreasing. This decrease appears to be the trend in arid, tropical and arctic areas. Meanwhile, rainfall in temperate locations appears to be increasing. However, even with the limited amount of information we have, we can already see that the heaviest storms are dropping more rain than they were before.

Similarly, the frequency of rain seems to be falling. Areas that get rain daily are starting to get it less often, and areas that rarely get rain are also getting it less often. The rain that does come is more intense. Therefore, while sectors that get rain frequently might have an almost unnoticeable increase in rainfall, the areas that are drier may see an increase in severe storms and flooding.

What does this mean for the future?

It’s hard to narrow these global results down to one reason. There are changes in land use, and people are moving into more flood-prone areas as the population increases. If you are one of those people, make sure you know how to protect yourself. Summer flooding may become less frequent overall, but it’s highly dependent on where you live and what the climate in your area already is.

It’s also important to note that rainfall is not the only cause of flooding. Coastal areas are at risk of an increase in severe storms like hurricanes, and the rising sea level, coupled with the storms, is a recipe for disaster. In fact, coastal areas are expected to have a 50 percent increase in flooding from storm surges by 2050.

All of this is hard to predict, and no one is certain of the events, but it’s best to be prepared either way. Even if people can’t agree on what floodwaters will do, the climate is changing. Several dangers go along with that, and flooding is just one of them.


This is a guest post written by Kate Harveston.
Kate Harveston is a freelance writer and blogger. Her writing focuses on politics and the environment, with a particular emphasis on social change. You can follow her writing by visiting her blog, Only Slightly Biased.

Written by Kate Harveston