Then along came the promise of nuclear fusion — a method that Then along came the promise of nuclear fusion — an energy-producing method that, unlike current nuclear power, produces almost no carbon emissions and creates a minimal amount of radioactive waste. Oh, and it’s also heralded to combat the worst effects of climate change at the same time. Not bad, right?

The allure of fusion energy is not its price but that very potential to help create power with virtually zero carbon emissions. The reality is, however, that the promise of such a clean energy source has yet to be realised, and instead, we are left with the problems associated with the radioactive waste that comes from nuclear power plants.

So, will — or even, can — fusion arrive in time to save us from the worst effects of climate change?

Unfortunately, the answer is likely no. What we do in the next two or three decades to reduce carbon emissions is crucial to determining whether the planet will become uncomfortably or catastrophically warmer by the end of the century. Although fusion power may help to rebalance the energy economy in the second half of the century, they will not come to our rescue in time to prevent the most severe consequences of climate change.

Despite the hype around advances in fusion science and technology, there are still uncertainties and unknowns. One such breakthrough was announced last December by the National Ignition Facility (NIF) of the Lawrence Livermore National Laboratory in California. The NIF team claimed to have produced more energy in their reaction chamber than they had put in to get the fusion process under way, but this is still far from breaking even.

The cost of making and operating a magnetic confinement device, like a tokamak, is eye-watering, and many engineers have been grappling with this for decades. Hopes are pinned on the International Thermonuclear Experimental Reactor (ITER) being built in southern France. ITER won’t be a power plant, but rather an experimental facility with the goal of solving some of the engineering problems to determine what a commercial fusion plant should look like.

The construction of ITER’s tokamak began in 2013, and the facility is already way over budget, with the current estimated cost being €20bn. It was recently announced that it might not switch on until 2035 or later. But such setbacks are to be expected when attempting to make a piece of a star on Earth.

Other countries, like China, Japan, and Russia, also have their own plans for fusion energy, and there are several dozen private companies worldwide with ambitious goals. While most experts believe we’ll be lucky to have a prototype plant producing a net gain by 2040, it’s unlikely that fusion energy will be going into the grid in significant amounts before 2050.

When fusion start-ups make promises about having a working reactor generating power within a decade, it’s typically a message for investors rather than a realistic promise. Companies like these will have their part to play, not as the plucky underdogs who crack the problem, but as providers of parts and expertise in the fusion industrial ecosystem.

However, researchers worry that over-promising could foster complacency that stymies investment in the urgently needed stopgap alternatives to fossil fuels, such as renewables and nuclear fission (fusion’s long distant cousin).

Lev Artsimovich, a Soviet fusion pioneer, once said that humankind would have fusion energy “when society needs it.” In one sense, he was mistaken; we needed it years ago, before the lethal heatwaves, wildfires, and shrinking ice caps. It’s not too much to hope that we will have it before we make the planet uninhabitable and that it can eventually turn the climate crisis into a catastrophe averted.

I will say that we should remember that progress in fusion energy research is slow, and setbacks are frequent just like most other scientific revolutions — and this would certainly be up there as a “big one”. We mustn’t lose sight of the fact that the potential of this technology is enormous. Our ability to master fusion will unlock virtually unlimited energy, without the harmful carbon emissions that threaten our planet’s future.

The road ahead is challenging, but if we can get fusion right, the rewards will be limitless.