But the IPCC also describes hundreds of strategies that could help humanity achieve this goal. Indeed, the report makes clear that there is no one silver bullet to solving global warming. Instead, nations, businesses, communities and individuals all have a role to play in shaping a safer and more sustainable future.
Here are six approaches highlighted in the thousands of pages of Monday’s assessment:
Switch on renewable energy
Electricity and heat production account for the largest fraction of planet-warming pollution — about a quarter of global emissions. That makes this sector one of the most important targets for climate policy. To have a shot at limiting warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit), the world must cut energy emissions between 38 and 52 percent in the next eight years.
Thanks to huge advancements in renewable energy technology, electricity generated from solar and wind is in many places cheaper than power from fossil fuels, the IPCC says. Small-scale renewable power sources, such as off-grid solar panels, can help bring electricity to communities that previously had no energy access.
Governments can use policy measures such as taxes on carbon emissions, financial incentives for installing renewables and renewable portfolio standards to accelerate the transition to clean energy sources, the IPCC says. Investments in energy efficiency can also help curb overall demand for power.
“Fundamental to all of these changes is that low carbon energy systems will use far less fossil fuel than today,” the authors write.
Make buildings more efficient
Emissions from buildings accounted for roughly 21 percent of greenhouse gases spewed into the atmosphere in 2019, according to the IPCC. That number includes indirect emissions from the power used for electricity and heat, as well as emissions from the use of steel and cement.
Decarbonizing the world’s buildings won’t happen quickly or easily. But widespread efforts to create more efficient and climate-conscious buildings could have profound impacts in helping the world reduce its carbon pollution. Some strategies include better insulation, more efficient heating and cooling systems, powering buildings with more renewable energy and using more sustainable construction materials — as well as public policies and financial incentives to encourage such approaches.
Turn cities clean and green
Cities, home to more than half the world’s population, are essential to tackling climate change. Urban land areas are projected to roughly triple by 2050. If expanding settlements are built using conventional materials and technologies, such as carbon-intensive concrete and car-centric transportation systems, it will “lock in” greenhouse gas emissions for generations to come.
Yet “deep decarbonization and systemic transformation” can turn cities into epicenters of the energy transition, scientists say.
Simple urban planning measures, such as increasing density, mixing residential and commercial areas so people can live where they work, and developing along public transit corridors, could cut urban carbon pollution by roughly a quarter by 2050. Using recycled materials in construction and heating buildings with electricity instead of gas can further slash emissions. Investing in green space can make cities safer amid worsening heat waves and intensified flooding while also pulling carbon out of the air.
Established cities can achieve the biggest emissions cuts by retrofitting buildings, adding new construction to boost the density of already populated areas and switching their energy systems to cleaner sources. But the real opportunity is in new and emerging cities, which the IPCC says have “unparalleled potential to become low or net zero GHG emissions while achieving high quality of life.”
Rev up electric vehicles — and walk or bike the rest of the way
How people fly, drive and ship goods accounts for a significant amount of greenhouse gas emissions around the world. Transportation is the biggest source in the United States. Emissions from the sector need to fall sharply in coming decades to put the world on a better path to meet its climate goals.
Some ways to move toward that goal, according to Monday’s report: Ramp up electric vehicles, explore hydrogen and advanced biofuels for aviation and shipping, embrace cultural and behavioral changes such as more telework and urban planning that allows people to use more public transit or travel by foot or bicycle. Technological assistance and smart transportation planning could allow developing countries to “leapfrog" past the need for fossil-fuel based transport systems, with benefits for air quality as well as climate, the authors write.
Sink carbon back into the land
Human-managed land areas are a significant source of planet-warming pollution, accounting for 13 to 21 percent of humanity’s emissions, depending on the year. But the land can also be a tremendous ally in the fight against climate change by pulling carbon out of the atmosphere — if people learn to manage it the right way.
One major area for improvement is in the way people farm, the IPCC says. Standard techniques such as tilling the soil and using lots of fertilizer release tons of greenhouse gases, and microbes in the guts of goats and cattle are a major source of problematic methane. By adopting regenerative farming practices that store carbon in the soil, curbing fertilizer use and reducing the amount of meat we consume, people can turn farmland from a carbon source into a sink.
Protecting nature, especially forests and other carbon-rich ecosystems, is also essential to halt the Earth’s warming trend. Healthy forests, restored wetlands and undisturbed prairies can pull billions of tons of carbon out of the atmosphere each year, the IPCC says — delivering as much climate benefit as almost 2 million windmills. Ecosystem recovery also protects wildlife, defends against heat and flooding, cleans the air and water and improves people’s mental health. Few other strategies deliver as much environmental bang for your buck.
Invest in a fairer world
The IPCC report makes clear that the people who suffer the most from climate change are those who contributed the least to the problem and have the fewest resources to deal with it. Least developed countries contribute about 0.4 percent of humanity’s cumulative greenhouse gas emissions, while developed nations — home to roughly the same number of people — are responsible for 27 percent of the world’s carbon pollution.
Since the dawn of the Industrial Revolution, rich countries grew their economies and improved their citizens’ quality of life by using fossil fuels. Yet if the world is to avoid catastrophic warming, the IPCC says, these wealthy nations must now help poorer ones achieve growth using renewable energy sources and sustainable development practices instead of coal, oil and gas.
Climate change brings irreversible harm to poor countries. Rich ones face pressure to foot the bill.
This requires a three to sixfold increase in funding to help developing countries cut their emissions, the report finds. Vulnerable regions will also need far more support as they adapt to the climate impacts they cannot avoid. But so far, the world’s wealthy countries have failed to fully live up to their financing promises they made to developing nations.
The world must address inequity as it fights climate change, the IPCC says, because it bolsters cooperation. And, if done right, efforts to curb emissions — such as installing solar panels in isolated communities, providing electric bikes to low-income city dwellers and restoring land management authority to indigenous people — can also improve the well-being of people.
“Reducing greenhouse gas emissions can contribute to ending poverty and hunger,” said environmental sociologist Patricia Romero Lankao, a lead author of the report, “when it’s done with justice and equity approaches in mind.”