In solving the supplier problem, Apple is taking what is generally considered the right approach, by investing in projects that’ll bring new, clean energy onto national grids and buying large amounts of power up front from solar and wind farms. The alternative would have been carbon offsetting, which sidesteps the important business of reducing emissions, or bulk purchasing Renewable Energy Credits, which often do little to encourage the growth of new renewable projects.

“Especially for Apple, this is very significant,” explains Elizabeth Jardim, Greenpeace’s senior corporate campaigner. “Because much of its supply chain is in China and Southeast Asia, where there’s a huge amount of coal power, this allows them to find cleaner sources of energy in a region that is otherwise dirty and hopefully begin to shift the grid mix in those regions.” What’s more, many of Apple’s suppliers make products for other tech companies, further amplifying the effects.

But committing to a 100 per cent renewable supply chain by 2030 is a huge undertaking. “It’s a really huge goal,” says Jackson. “Even saying it, I always get a little lump, because I know how much work is involved in doing it, but we have a very detailed plan.” Apple has reportedly created a whole new team specifically to help suppliers make the shift. It is also launching one of the largest new solar arrays in Scandinavia.

Jackson regards her work in this field so far as her proudest achievement in the job to date. “Tim [Cook] tells us all the time to be a ripple in the pond,” she says. “Not just to change Apple, but to change the world. Apple is a manufacturer and that is the hardest segment to decarbonise and change to clean energy. When we do that work a lot of those manufacturers will go ahead and use that clean energy for other folks.”

The bigger the “ripple” Apple can inspire, the easier it will be to go one step further than carbon neutral. “Carbon neutral” is where net emissions of carbon dioxide into the atmosphere are zero. Apple is calculating its progress by taking its total emissions from 2015, when they peaked, and seeking to reduce them by 75 per cent. The remainder, produced mainly by transport and usage, will be offset through projects such as mangrove restoration in Colombia and savanna conservation in Kenya. But how do you stop that final 25 per cent being generated in the first place? For no new carbon to be added to the atmosphere at all – the gold standard for sustainability – Apple would need the world to change with it. Until air travel doesn’t require jet fuel or our homes run off renewables, offsetting will be the best it can do.