The Intergovernmental Panel on Climate Change reports we have 12 years to dramatically cut emissions to avoid locking in dangerous global warming, but the World Meteorological Organization announced atmospheric emissions are higher than at any point in the past 3-5 million years and emissions grew again in 2018 after several years of zero growth.

After the COP24 climate summit resulted in only moderate outcomes, there’s no doubt we must act swiftly on climate change – we’re now in a state of climate triage.

Climate change’s damages to our economy are mounting – Hurricanes Michael and Florence, along with two California wildfires, cost roughly $45 billion in 2018 – and each passing day we fail to act makes preventing dangerous global warming much more difficult.

World leaders must assume the role of an emergency room doctor trying to save a patient’s life: Identify the worst threat and take swift action to fix the gravest injuries. For climate, this means identifying where the greatest emissions are coming from and then rapidly decarbonizing those sources.

Assessing the emissions damage

Just like an ER doctor would work fast to identify her patient’s worst injury and stop the bleeding, world leaders must start climate triage by first understanding where the greatest emissions are coming from and where to focus our decarbonization efforts.

Nearly 75% of global greenhouse gas emissions come from the top 20 emitting countries, so targeting emissions in these 20 countries is the largest and fastest opportunity to reduce emissions, as outlined in Designing Climate Solutions.

But knowing which countries create the most emissions is not enough; we must identify the biggest sources of emissions. Emissions come from a relatively small set of sources: Burning coal, natural gas, and oil in power plants; burning fossil fuels for electricity and heat in industry; burning oil in car, bus, and truck engines; and burning natural gas, oil, and coal in buildings for heat, cooking, and lighting.

Industrial process emissions, for example methane leaked from natural gas pipes and carbon dioxide (CO₂) released in cement manufacturing chemical processes, are surprisingly significant sources of emissions. Finally, land use emissions are significant in particular countries, making deforestation, which reduces the ability of forests to absorb and store CO₂, an important area to focus on in those countries.

World leaders can stop the bleeding to save their patient: In the 20 largest-emitting countries, reduce fossil fuel consumption in power plants, factories, automobiles, and buildings; and cut industrial process emissions.

An action plan for saving the patient

In climate triage, just like a well-trained ER doctor knows how to address injuries, we know how to tackle emissions from each of these sources. In the power sector, we must push more zero-carbon technologies onto the grid, maintain the ones we already have, and retire fossil fuel power plants. The falling costs of wind turbines, solar panels, and batteries mean building new clean energy is cheaper than running existing coal generation in many parts of the world, putting this future in sight.

In industry, we must improve the efficiency of equipment and switch from coal or oil for power and heat to natural gas (or better yet, electricity where possible). Pueblo, Colorado’s EVRAZ steel mill utilizes electric arc furnaces to create heat for steelmaking by relying on electricity rather than coal or gas for heat, thereby avoiding emissions. Reducing process emissions is also a top priority as those emissions often contain potent greenhouse gases much worse for climate change than CO₂.

In the transportation sector, vehicles must consume much less petroleum and switch to low- or zero-carbon fuels like electricity and biofuels. By 2025, the falling costs of electric vehicles will be cheaper than internal combustion engines, helping accelerate the transition to a low-carbon transportation fleet. Similarly, electric buses are nearing cost-competiveness with fossil fuels, empowering zero-carbon public transport while saving cities millions of dollars in maintenance and fuel costs – the city of Shenzhen, China recently replaced its entire fleet of 16,000 diesel buses with electric ones.

Buildings also have significant energy efficiency potential. Better-insulated buildings reduce demand for energy services like heating and cooling, while more efficient equipment further cuts energy demand. The savings from these improvements can be huge, and in many cases pay for themselves over a short time period. Over time, buildings must also become largely electrified.

Climate triage through fast policy action 

Climate triage can tackle climate change by decarbonizing the power, industry, transportation, and buildings sectors. Fortunately, decades of global experience with climate and energy policy has proven which policies drive down emissions fastest and cheapest. A small set of well-designed, stringently set policies can put the world on a path to avoid the worst impacts of climate change.

In the power sector, renewable portfolio standards and feed-in tariffs can push more renewables onto the grid while helping reduce costs for new technologies. Innovative approaches to re-financing power plants and utility regulation can ensure we invest intelligently in the grid of the future while managing early retirement of uneconomic fossil power plants. Together these power sector policies can contribute 21% of necessary emissions reductions.

In industry, strong efficiency standards for motors, boilers, and other equipment can dramatically cut energy and emissions. Better control of process emissions, for example by capturing leaking methane from landfills and natural gas systems or through alternative lower-carbon processes like those being implemented in the iron and steel industry can reduce non-energy emissions. Together, these can deliver 27% of necessary emissions reductions.

In transportation, fuel economy standards and incentives can improve new vehicle efficiency while cutting consumer costs by lowering oil expenditures. New electric vehicle sales mandates, like the 5 million zero-emissions vehicle goal followed by California and nine other states, can help deploy more zero carbon cars, buses, and trucks onto our roads.  Improving urban designthrough better access to urban transit, improved zoning, and so on, also cuts emissions. Altogether, transportation sector policies can provide 7% of necessary emissions reductions.