It’s a law of physics that warmer air holds more moisture. Warm air holds water because the water vapour molecules in the air are moving at a higher average speed than those in colder air, making them less likely to condense back to liquid. The result of this physical law? For each degree Celsius that the air temperature rises due to greenhouse gas emissions, the atmosphere can hold 7% more water – meaning there is more potential for enormous clouds to form.
Water vapour cycles through the atmosphere quickly, unlike carbon dioxide that persists in the air for decades. However, water vapour is itself a greenhouse gas that compounds the warming from carbon dioxide emissions.
In a positive feedback loop that is not in the least positive for us, studies show that water vapour doubles the warming caused by carbon dioxide. In other words, if there is a rise in temperature of one degree Celsius caused by carbon dioxide, the resulting increase in water vapour will cause the temperature to go up another one degree – and so the air continues to warm up and hold even more water.
‘All or Nothing’ Rainfall
How this translates into changes in precipitation is not so linear, but the total volume increases and its uneven distribution becomes more exaggerated. Heavier rainfall is produced by fewer, more intense events that in turn lead to longer dry spells elsewhere.
Scientists have warned that because the UK is not storing its water properly, the country is vulnerable to the ‘all or nothing’ rain patterns experienced more frequently due to the warming atmosphere. In hotter summers, we face torrential downpours and flash flooding in some parts of the country while other parts have water shortages and hosepipe bans; in warmer winters, we endure longer saturated periods of wet weather with large parts of the country under water.
Local Climate Action
There are things we cando collectively to make the places where we live more resilient and to improve our capacity to adapt to our changing climate. On Carbon Copy you can find the latest local climate action plans for your area and learn more about the different projects people are implementing to adapt to the impact of too much or too little water. We’re all in the same boat and you may be able to lend a hand.
Search using the dropdown below to find the page for your local area:
