Decades before world leaders woke up to the risks of climate change, Jimmy Carter was a pioneer in promoting green energy and environmental policies.
The former US president, who has died aged 100, is often remembered as the man who installed solar panels on the roof of the White House in 1979 — only to have them ripped out by his successor Ronald Reagan.
But his environmentalism ran far deeper, and his vision for America continues to shape energy discussions to this day.
Mr Carter served one term in office from 1977 to 1981. It was a tumultuous time in the world's energy markets, and he came to power with the 1973 oil embargo during the Arab-Israeli war still fresh on America's mind.
In 1979, another oil shock came during the Iranian Revolution that led to a sharp drop in crude oil production. As in 1973, Americans had to queue to fill their cars and the crisis ultimately helped Mr Reagan defeat Mr Carter in 1980.
It was against this background that Mr Carter designed what his biographer Jonathan Alter called “the nation’s first comprehensive energy policy".
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He called for 20 per cent of America's energy to come from renewable sources by 2000, an ambitious target that has only very recently been met.
Mr Carter also pushed Americans to consume less energy, famously addressing the nation in 1977 and asking people to put on a cardigan and turn the thermostat down.
Mr Carter founded the US Department of Energy, which is responsible for developing new sources of fuel and is currently making advances in the field of nuclear fusion that promises to one day provide abundant, emissions-free power.
He also designated millions of hectares in the Alaskan wilderness as federally protected lands and signed into law the Superfund programme for cleaning up hazardous waste sites and spills.
In what today could be seen as a contradiction, however, Mr Carter was also a proponent of burning coal.
The effects of burning hydrocarbons on global warming were not as well understood in the 1970s, and back then, the main concern with coal was acid rain. But sulphur-dioxide scrubbers helped reduce the polluting rain and Mr Carter saw coal as a way of reducing US reliance on foreign oil.
Mr Carter's passion for solar energy only expanded after he left the White House.
In his hometown of Plains, Georgia, he installed thousands of solar panels that now provide enough energy for half of its residents.
At the 1979 dedication ceremony for the thermal solar panel units Mr Carter put on the White House roof, Mr Carter expressed his passion for green energy.
"A generation from now, this solar heater can either be a curiosity, a museum piece, an example of a road not taken or it can be just a small part of one of the greatest and most exciting adventures ever undertaken by the American people," he said.
