It's official: 2021 was the fifth-warmest year on record, and the seven hottest years on record have all come since 2015. Yet even as the planet warms and scientists sound the alarm, humans continue to pump massive amounts of greenhouse gases into the atmosphere. Just how massive?
Imagine a big, spherical balloon. One with a diameter of about 30 feet, big enough to swallow a city bus. If you pumped it full of carbon dioxide, it would weigh 1 ton. Now imagine a line of those balloons stretching from the Earth to the sun and back, and then to the sun again — almost a 300 million-mile trip. That’s how many balloons it would take to hold the world’s annual climate change-causing emissions.
Climate change is big. And while the urgency of the situation has seeped into public consciousness, our basic understanding of how to solve it is muddled by a blizzard of information.
Which actions would really provide the gains in the race toward carbon neutrality? Which others — however much we’ve heard about them — would barely move the needle?
Scientists say we must hold the rise in global temperature to within 1.5 degrees Celsius to stave off warming’s most catastrophic effects. Here’s a look at the contributions that would be made by major shifts in national and international policy, dramatic changes to heavy industries and making different personal choices we’re often told will help—such as eating less meat or flying less. There are paths to a cleaner, cooler world. Here are a few.
In 2019, humans worldwide collectively emitted a total of 52.4 gigatons, or billions of tons, of greenhouse gases. Scientists agree that to keep warming to 1.5 degrees Celsius, the world needs to cut its annual greenhouse gas output in half, to around 25 gigatons, by 2030, en route to complete carbon neutrality by 2050.
So how do we get there? Let’s start by looking at what would happen if every country met its commitment under the landmark 2015 Paris Agreement. These pledges, known as "nationally determined contributions" (NDCs) are meant to be updated; many nations did so at or just prior to U.N. climate talks in Glasgow, Scotland, in November. So what if every country met its goal?
National ambitions haven’t quite caught up to what’s needed just yet. But if international diplomacy makes some breakthroughs in the next year or two, nations will then need to meet their pledges through real action. What industries, sectors and actions might help push those national efforts where they need to go?
Let’s start with electricity production. It’s well known that coal is the dirtiest option when it comes to generating electricity; in fact, a recent study found that to meet the 1.5-degree target, 90 percent of all known coal reserves would need to remain unmined. What if we could just switch off every coal power plant today and switch on solar panels or other renewable sources of energy instead?
Electricity from fossil fuels
In the U.S., coal is on the decline; in 2020, it accounted for less than 20 percent of electricity generation. Natural gas accounts for twice that much. What if the U.S., the world’s second-biggest emitter, could immediately transition away from all its fossil fuel-fired electricity, both coal and natural gas?
It’s clear that the world needs a big boost from China, the world’s biggest emitter, to get where we need to go. China’s coal power sector remains a big issue for the climate — what if it transitioned away from coal entirely tomorrow?
Elsewhere in the developing world, electricity production is going to increase dramatically over the coming years. Many climate advocates are adamant that expansion in these countries must come in the form of clean, renewable energy. But some context is useful: One analysis found that if the 48 countries of sub-Saharan Africa (minus South Africa) tripled their electricity consumption using only natural gas power, it would add only a tiny amount to the global emissions pool.
Electricity production, of course, is not the only big source of emissions. One of the most climate-important industries that doesn’t always get much attention is cement production. Cement — used to make concrete and critical for buildings, bridges and all sorts of infrastructure — is responsible for around 5 percent of all global emissions. If it were a country, it would come in third or fourth, behind only China and the U.S. and similar to India.
There are a number of efforts to reduce emissions from cement production, involving changes to the process itself or advancing the use of carbon capture. One 2018 “technology roadmap” from the International Energy Agency laid out a path to reducing the industry’s impact. If it were followed to the letter, using everything from less carbon-intensive fuel during the manufacturing process to carbon capture and storage, here’s what would happen, even as actual production of cement keeps rising.
One thing to keep in mind is that emissions from cement, or other big industries like steel, aren’t spread evenly across the world. More than half of all cement production takes place in China. A recent Bloomberg analysis showed that just a single Chinese steel company (China Baowu Group) emits more than the entire countries of Belgium and Austria combined.
Another company, China Petroleum and Chemical Corp., would be the seventh-biggest global emitter if it were a country, ahead of oil-rich Canada — responsible for this much of the world’s total. In general, China has resisted promising specific CO2 cuts, but it did lay out a roadmap to decarbonization recently, and its promise to reach “peak” emissions by 2030 may in fact be ahead of schedule.
Globally, the steel industry also accounts for about 5 percent of all emissions. Eliminating that entirely isn’t in the cards, but some reductions are possible. The U.S. and EU may be on track to achieve 30 percent cuts in steel-related emissions soon — but they account for only 15 percent of all steel production. China, which uses generally dirtier technology, accounts for 53 percent.
China may produce a lot of the world’s steel and cement, but it’s important to remember who is using it. The U.S., as of 2019, remained the world’s largest importer of cement. Emissions get very complicated very quickly once we start pondering the global flows of all these goods.
Some of the world’s emissions don’t come from building and powering things, but from destruction. Globally, deforestation and forest degradation contribute an enormous chunk of emissions. It is obviously a complicated project, but if we could just … stop doing that … here’s what it would look like.
Most of that deforestation is occurring in Brazil, Indonesia and other tropical countries. The products made using the cleared land are often sent abroad to rich places like the U.S. and Europe.
Hopefully this is helping to clarify the scope of the issue, how tough it is to really make a dent in the global emissions picture, and how the impactful change will have to come from major national and international policy shifts as well as dramatic changes to heavy industries. But what about some of those more personal actions we’re often told will help — such as eating less meat. Where do they fit in?
Meat and dairy production account for a hefty chunk of global emissions – an estimated 7.1 gigatons. So what if we could convince the entire planet to go vegan?
Meat and dairy
Not bad! But maybe that’s unrealistic. How about we all switch to a “climate carnivore” diet, where 75 percent of red meat is replaced with other meats?
Might be tough to get every country on Earth to follow suit. What happens if just Americans went “climate carnivore,” based on the percentage of global population?
But what about some other choices we can make? Take flying. Air travel accounts for about 2 percent of all global emissions (though it is responsible for more than 3 percent of warming, due to other atmospheric changes planes cause), so if every single flight stopped tomorrow, we could take a small but reasonable bite out of the total.
Zero flying, of course, isn’t realistic. The International Air Transport Association (IATA) has a goal of reducing aviation emissions by 50 percent from 2005 levels by 2050, using a combination of better aviation fuels and improved infrastructure and technology — even while expanding the number of flights in total. If IATA can pull that off, what would it look like?
If you do travel by air, it’s likely to be your own single biggest source of emissions. A round trip from New York to London generates more than 2,000 pounds of CO2 per passenger —already about 1/16th of an average American’s yearly footprint. But two-thirds of all flights are taken by only 12 percent of Americans, and more than half of the country doesn’t fly at all in any given year.
Transportation is an important sector, accounting for about 15 percent of the global emissions total. Decarbonizing all those cars, trucks, planes and more will be a challenge. The main way individuals can help is by switching from gas-powered cars to electric ones. EVs don’t have any tailpipe emissions, but they’re not 100 percent emissions-free thanks to the process of building them, as well as the need to charge them using not-necessarily-clean electricity sources. At the moment, an electric car generates about a third of the emissions of a gasoline-powered car. But if electricity sources in the U.S. were all clean and most of the passenger vehicles in the country went electric? That could cut 90 percent of emissions from the sector, or almost 2 percent of the global total.
The Biden administration has set a goal of making at least half of all new vehicles sold in 2030 electric, but increases in renewable power will have to accompany that move to make it truly effective.
Cutting out meat is something you do have under your control — as opposed to, say, the source for the power plant keeping your lights on —so if you want to do your part then it’s a decent start. And yes, every bit matters! But individual actions only go so far in comparison to big government moves.
We’ve seen where the big problems and big opportunities lie. The longer we wait to make significant cuts in global emissions, the steeper and faster those cuts will have to
be if we want to achieve the Paris Agreement’s ambitious target of holding warming to 1.5 degrees Celsius, or even 2 degrees, or even more if the recklessness continues.
52.4 gigatons of greenhouse gas emissions
ALL NDCs MET
No more coal
U.S. TRANSITIONS AWAY FROM FOSSIL FUEL-FIRED ELECTRICITY
AWAY FROM Coal
Cement production eliminated
steel industry eliminated
world goes vegan
global climate carnivore
stop all air travel
IATA Emissions Goals Met
U.S. Passenger vehicles go electric
make a different color
make a different color
All NDCs met
U.S. passenger vehicles go electric
World goes vegan
No more coal
Meat and dairy
Side by side
Visualizing what matters most in the climate fight
By Dave Levitan
Illustrations by Mae Decena
Art Direction by Shaylyn Esposito
It's official: 2021 was the fifth warmest year on record, and the seven hottest years on record have all come since 2015. Yet even as the planet warms and scientists sound the alarm, humans continue to pump massive amounts of
greenhouse gases into the atmosphere. Just how massive?