Five Factors of How Climate Change Affects Flooding

1. A warmer atmosphere holds more moisture

The atmosphere is about 0.75 degrees hotter than it was at the beginning of the millennium, according to the Intergovernmental Panel on Climate Change (IPCC), which implies it can maintain 5–6 percent more humidity.

That does not automatically imply heavier rainfall for the whole world because the quantity, timing, and distribution of rainfall are governed by complicated weather patterns. But it does imply that the quantity of rain may increase when it pours with more water in the atmosphere.

However, this is not the end of it, as climate change can impact atmospheric circulations such as the Jet Stream, which regulates weather systems moving across the UK. However, research on this is still quite new, and the connection, for now, remains less than certain. But it’s another reason why it’s complex to connect climate change to flooding.

2. Evidence of heavier rainfall in the past is limited, but growing

Extreme occurrences are uncommon, and it takes decades of ongoing observations to detect trends outside of natural variability. Thus, while there is a theoretical connection between climate change and rainfall, it is still difficult to locate clear proof because the measurement record is brief and does not cover all sections of the globe.

Globally, as the IPCC concluded in its Special Report on Extreme Events, this makes it difficult to differentiate any trend in the intensity or frequency of flooding due to climate change. But there is some proof in Europe, where there are more data on rainfall, for a trend towards heavier rainfall.

The latest research found that greenhouse gas emissions between 1950–2000 contributed to findings of more intense precipitation over two-thirds of the northern hemisphere. With a tiny set of rainfall information, finding patterns like this is hard, but it should become clearer as more extreme occurrences happen over time.

3. Attributing specific events to climate change is tricky, and flooding is no exception

In particular, researchers are cautious about attributing particular extreme occurrences to climate change because it is difficult to say that if global temperatures did not rise, an incident would have occurred. Considering how climate change might have contributed to the frequency or severity of such occurrences is more helpful.

A recent study found that while it is difficult to identify the precise human contribution to widespread flooding in England and Wales in 2000, global greenhouse gas emissions increased flood risk by up to 90%. Such thorough information assessment requires time and it is not yet feasible to link the present UK flooding with climate change.

4. Scientists predict that heavy rainfall will increase in the future

Flooding takes place in a number of respects, and climate change can affect everyone. Flooding of surface water occurs where heavy rainfall cannot absorb or drain away from the floor. River flooding happens when streams burst their banks, strongly connected to ground flooding. The result of elevated tides, storm surges, and sea level increase is coastal flooding.

Higher sea levels pose a definite danger to coastal regions of flooding. But in surface water and river flood predictions, there is less certainty. This is primarily due to modeling uncertainty and difficulty simulating how weather patterns can change.

However, based on physical reasoning, many studies–including public research on climate change hazards–predict that in the future, especially during the winter, the world will experience more severe rainfall and more frequent elevated river flows. This is echoed in the latest study by the European Environment Agency (EEA), which predicts rises in UK river and coastal floods.

5. Flooding isn’t just about rainfall; other human factors contribute too

Flooding and severe rainfall go hand in hand, but it’s not the same thing. While climate change in the UK can directly alter precipitation, flooding is a result of heavy rainfall that also has a human element.

The increasing cost of flood-related damage is an ideal illustration. The increase might be down to a number of variables, not just the amount of rain falling. People are getting better at reporting damage, but there is also a significant effect on human operations.

Changes in land use, such as the construction of buildings on flood plains and paving over natural surfaces, make individuals more susceptible to flooding.