Hotter drier summers and less predictable rainfall as a result of climate change will lead to increased drought risk and possible water shortages in the UK, Environment Agency chief executive Sir James Bevan has warned today, as he argues for the need for an increased focus on water quantity alongside water quality as we begin to feel climate impacts.

Speaking at the Royal Society, Sir James has also sent a reminder to world leaders of the irrevocable damage that climate change has already done, meaning that climate adaptation must be a key priority in Glasgow alongside action to reduce emissions.

The Environment Agency’s estimate is that summer rainfall is expected to decrease by approximately 15% by the 2050s in England, and by up to 22% by the 2080s; and that by 2100 in the south-east we will increasingly see temperatures above 35°C, and sometimes 40°C.

With this in mind, Sir James spoke of the importance of an increased focus on adaptation measures to avoid hitting the “Jaws of Death” – the point on water companies’ planning charts where water demand outstrips supply:

Good water quality is essential, but the right water quantity is existential. We need as much emphasis on the latter in the future as we have now on the former.

We know what to do to avoid those jaws: reduce demand, by using less water more efficiently; and improve supply, including by investing in the right infrastructure. That means we need to think strategically, radically and long term.

The Environment Agency’s National Framework for Water Resources identifies England’s long-term water needs up to 2050, and also identifies the actions needed by water companies, government and others – including halving leakage, reducing demand, and developing new supplies – to safeguard future supply. The Environment Agency has set up mechanisms to deliver these goals and is working with the water companies, other regulators and the government to ensure they get done.

Sir James has reminded leaders that while the world hopes for a successful COP26 in the coming weeks, the damage that has already been caused by human activity means that the impact of climate change is already here will continue to be felt for decades – including through more flooding, wildfires, drought and damage to wildlife. The only way to tackle that is to adapt to our changing climate so that we are resilient to its effects:

However successful COP26 is, it won’t stop the climate changing or all the effects of that change, because human activity to date means that some irrevocable climate change has already happened and that more will continue to happen, even if the world stopped all carbon emissions tonight.

We are seeing such big climate shocks today at just over 1 degree of warming above pre-industrial levels. On our present course temperature rise will soon be teetering on the edge of +1.5°C, with +2°C or more in sight, which means these shocks will intensify.

That is why as a nation we need to be climate ready - resilient to the future hazards and potential shocks that we already know will impact on all our lives.

Sir James has also outlined his optimism in tackling the climate emergency as we look ahead to COP26 in Glasgow:

The good news is that we still have time to avert climate catastrophe.

There is now mass public pressure around the world to solve this crisis. That is driving governments to take action they were not prepared to take before, such as the recent commitments from the United States on green finance and from China on coal.

I believe in humanity. Since the last ice age receded, we humans have done a lot of very stupid things, and causing global warning that threatens to destroy us as species has to be top of that long list. But humans have also done remarkable things that have made the world we live in a far better place. Our ingenuity as a species caused this mess, and it can get us out of it.