The solution to human-induced climate change is finally in clear view. Thanks to rapid advances in zero-carbon energy technologies and sustainable food systems, the world can realistically end greenhouse gas emissions by mid-century at little or no incremental cost, and with decisive benefits for safety and health.
The main obstacle is inertia: Politicians continue to favor the fossil-fuel industry and traditional agriculture mainly because they do not know better or are on the take.
Most global warming, and a huge burden of air pollution, results from burning fossil fuels: coal, oil and gas. The other main source of environmental destruction is agriculture, including deforestation, excessive fertilizer use and methane emissions from livestock.
The energy system should shift from heavily polluting fossil fuels to clean, zero-carbon energy sources such as wind and solar power, and the food system should shift from feed grains and livestock to healthier and more nutritious products.
This combined energy-and-food transformation would cause net greenhouse gas emissions to fall to zero by mid-century and then move into the negative, as atmospheric carbon dioxide is absorbed by forests and soils.
Reaching net-zero emissions by mid-century, followed by negative emissions, would likely secure the goal of limiting global warming to 1.5°C relative to Earth’s preindustrial temperature.
Alarmingly, warming has already reached 1.1°C and the global temperature is rising about 0.2°C each decade. That is why the world must reach net-zero emissions by 2050 at the latest.
The shift toward clean energy would prevent hundreds of thousands of deaths each year from air pollution, and the shift to healthy, environmentally sustainable diets could prevent about 10 million deaths per year.
A low-cost shift to clean energy is now feasible for every region of the world, owing to the plummeting costs of solar and wind power, and breakthroughs in energy storage.
The total system costs of renewable energy, including transmission and storage, are now roughly on par with fossil fuels. Yet fossil fuels still get government preferences through subsidies, as a result of incessant lobbying by Big Coal and Big Oil, and a lack of planning for renewable alternatives.
The key step is a massive increase in power generation from renewables, mainly wind and solar. Some downstream energy uses, such as automobile transport and home heating, would be directly electrified. Other downstream users — in industry, shipping, aviation and trucking — would rely on clean fuels produced by renewable electricity.
Clean, or zero-emission fuels include hydrogen, synthetic liquids and synthetic methane.
At the same time, farms should shift toward plant-based foods.
Asia’s continued construction of coal plants, together with ongoing deforestation in Southeast Asia, Africa and Brazil, is putting our climate, air and nutrition at huge and wholly unnecessary risk.
In the US, the promotion of fossil fuels by US President Donald Trump’s administration, despite the US’ vast renewable-energy potential, adds to the absurdity.
So does the renewed call by Brazilian President Jair Bolsonaro to develop — that is, to deforest — the Amazon.
So, what to do?
The most urgent step is to educate governments and businesses. National governments should prepare technical engineering assessments of their countries’ potential to end greenhouse gas emissions by mid-century, while businesses and banks should urgently examine the technologically compelling case for clean, safe energy and food systems.
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