To tackle dangerous global warming, countries have started to clean up their power plants and cars. But emissions from heavy industry — like cement, steel or chemical factories — have been harder to curb and are now on pace to become by far the world’s largest source of planet-warming pollution.
That’s one big takeaway from a new, detailed forecast of global greenhouse gas emissions published Thursday by the Rhodium Group, a research firm. Overall, the report estimates that the world is currently on track to heat up roughly 2.8 degrees Celsius, or 5 degrees Fahrenheit, above preindustrial levels by 2100. Many world leaders and scientists consider that much warming to be perilous.
Trying to predict emissions so far out in the future is inherently difficult, but the forecast offers a rough guide to where countries appear poised to make progress on climate change in the years ahead — and where they are still struggling.
Where Emissions Are Projected to Fall
Globally, greenhouse gas emissions are expected to soar to record highs this year. However, there are signs that planet-warming pollution from two major sectors — electricity and transportation — could start declining in the not-so-distant future.
In the electricity sector, which accounts for one-quarter of greenhouse gases today, countries may be on the verge of a breakthrough. Solar and wind power are growing so fast that some experts now expect global demand for fossil-fueled electricity to peak this decade. That process has already started in the United States and Europe, where coal-fired power is plummeting, and China could soon follow.
Carbon-dioxide emissions from transportation are also projected to fall by midcentury because of the rapid spread of electric vehicles, which now make up one in five new car sales globally. In places like Africa and Asia, smaller electric motorcycles, mopeds and rickshaws are already displacing nearly one million barrels of oil per day.
Still, the report notes, neither electricity nor transportation appears to be on track to get all the way to zero emissions — which is what scientists say is ultimately needed to halt climate change.
That’s because most countries still rely on coal or natural gas to back up wind and solar power, and there are aren’t yet obvious solutions for decarbonizing long-distance trucks, airplanes and ships. Until nations solve those challenges — perhaps with new types of batteries, advanced nuclear reactors or clean hydrogen fuels — they will remain partly dependent on fossil fuels like oil and gas.
“Eventually we reach the limits of what we can do with technologies widely available today,” said Kate Larsen, a partner at the Rhodium Group. That, in turn, could cause emissions to start rising again later this century if electricity and travel demand continue to grow.
To make its forecasts, the Rhodium Group considered a wide range of estimates for economic growth, oil and gas prices, the costs of clean energy and policy trends. The forecasts for the latter half of the century are particularly uncertain because it’s tough to predict how technologies, economies, politics and demographics will change.
There are also countless buildings around the world that burn coal, oil or natural gas for heating and cooking. Those emissions are projected to fall modestly over the next few decades, in part because of efficiency improvements and a shift to cleaner electric technologies like heat pumps, the report said. But without stronger action, such as a push to retrofit older homes and buildings, emissions are unlikely to fall to zero.
Where Emissions Are Projected to Rise
Industry — which includes production of iron, steel, cement, chemicals, oil and gas — remains one of the hardest sectors to clean up. It also often gets overlooked in climate discussions. But industrial emissions are currently expected to soar in the decades ahead.
They come from a vast array of sources. Many factories burn coal or natural gas to produce huge amounts of heat needed to create steam, temper glass or turn iron into steel. Cement makers emit carbon dioxide as part of the process of transforming limestone into cement. The chemical industry uses fossil fuels as a raw material for its products.
In theory, there are technologies that can cut emissions. Industrial heat pumps or thermal batteries could help factories generate heat from renewable electricity. Cement makers could capture and bury their carbon dioxide. Steel makers could use clean hydrogen instead of coal. But many of those solutions are expensive and in their infancy.
“There aren’t many clear winners that have emerged just yet,” said Morgan Bazilian, a professor of public policy at the Colorado School of Mines. Some governments have also been hesitant to crack down on industrial emissions out of concern that factories and jobs could shift abroad to places with looser environmental rules.
Without cleaner alternatives, industry is projected to become the world’s biggest climate change problem by far. In the Rhodium Group’s forecast, cement manufacturing alone is expected to produce twice as many emissions for the rest of the century as all of the world’s cars combined.
The biggest growth in industrial emissions is expected to come from emerging markets such as India, China, Southeast Asia and Africa. Yet many of the most promising early attempts to decarbonize cement or steel are happening in wealthier places like the United States and Europe.
“There’s a massive mismatch there,” said Anna Nilsson, a climate policy analyst at the NewClimate Institute who recently helped write a comprehensive report on the world’s progress in cutting emissions from industry and other sectors. “There’s a huge need not just to develop cleaner technologies but also to make sure that they can be used everywhere.”
The Rhodium Group analysis also projects a rise in emissions from agriculture, particularly in places with significant population growth like Africa, India, Brazil and Southeast Asia, where forests continue to be cleared away for farmland. As societies grow wealthier, they also tend to eat more meat, which has a high climate impact.
One of the best strategies for reducing agricultural emissions, experts say, would be to increase crop yields — that is, grow more food on less land. One recent report found that improvements in crop technology and farming practices are making farms more productive, but the changes aren’t happening fast enough. And many nations are falling behind on a recent pledge to reverse and halt deforestation by 2030.
The Rhodium Group’s temperature forecast is broadly in line with other analyses, including those from the International Energy Agency and Climate Action Tracker. But it differs in other ways, like taking a more detailed, long term view of emissions and assuming that climate policies will continue to evolve in line with historical trends.
In the future, however, countries could take much more aggressive action than they have in the past, said Joel Jaeger, a senior researcher at the World Resources Institute who was not involved in the report.
“The fossil fuel industry might look at these current policy projections and think that oil and gas demand will still be high all the way out in 2100,” Mr. Jaeger wrote in an email. “But if countries put in place new policies to meet the Paris Agreement and their net-zero pledges, that’s absolutely not the case.”