You might not know it from the summit photocalls and pageantry, but the imminent retirement of nuclear power plants is one of the biggest threats to the progress of decarbonisation across the G7.

Nuclear provides the G7 more clean power than any other source. By 2040, however, more than 100 GW of nuclear capacity is due to retire. This would represent the single greatest loss of clean power in world history and will overwhelmingly affect the G7 countries. The United States and France produce more nuclear power than any other country from fleets built mostly in the 1970s and 1980s. Dozens of reactors are thus nearing the end of their original design lives. Canada will lose one of its major plants in 2024, and in the UK, five of our eight stations will retire by 2024, the fastest loss of any G7 country.

Two other G7 countries, Germany and Japan, show what the consequences of these retirements could be without new investment. A Columbia University study found that Japan’s nuclear shutdown in 2011 caused an extra 480 million tonnes of emissions and 2300 deaths from the consequences of extra coal and gas burning within just six years. What is more, Japan missed the opportunity to prevent 21,000 premature air pollution related deaths and 1.7 billion tonnes of emissions by choosing to reduce its nuclear output rather than reducing its coal burning. Germany could have prevented 4,600 premature deaths and 300 million tonnes of emissions from 2011 to 2017 alone. Those numbers will rise if, as planned, the rest of the Germany nuclear fleet is shuttered before its time.

The G7, and the UK within it, should not embrace these outcomes. As the Japanese Energy Minister himself has said “nuclear power will be indispensable”. So what can we do? We can ensure equal access to climate finance for nuclear projects, extend the life of our existing plants where possible, and invest in new plants wherever we can. Our existing reactors are “one of the most cost-effective sources of low-carbon electricity”, according to the IEA. New reactors will allow us to harness new designs and innovations to provide this power-hungry world with the low-carbon energy it needs.

There are those who try to avoid ever saying the word nuclear, and who pretend that we can meet net zero without it. The blunt truth is that net zero needs nuclear. Only nuclear can replace nuclear, so we have to get life extensions or new plants for every watt of capacity scheduled to go offline. We also need a lot of new nuclear to replace the gas and coal that the UK and other G7 countries continue to burn. Fossil fuels have survived because they keep the lights on, whatever the weather, whatever the time of day. Nuclear does the exact same thing, but with no emissions. So, it’s a no-brainer to invest in nuclear. This is how we make progress toward our climate goals, rather than sliding further from them.

The G7 countries should be at the forefront of a new era of nuclear investment. These countries were the pioneers of civil nuclear power. We have a long history of cooperation in technological innovation and economic development. Our regulators, academics and companies share expertise and insights every day. As we face a generational challenge, we should support each other in mobilising investment and driving innovation to get the job done.