 Since the Industrial Revolution, humans have emitted more than 2,000 gigatons of carbon dioxide into the atmosphere. That's the weight of more than 400 billion African elephants, 5.5 million Empire State Buildings, or 347,000 Great Pyramids. This thickening blanket of heat-trapping greenhouse gases has a tremendous effect on the climate and the world we live in. If you guys want, in a future video, we can explore how we're trying to reduce our emissions or the effects those emissions have on our planet. But today, we're going to be talking about six ways that we're trying to actively remove CO2 from the air. So let's jump in. While the expansion of renewable energies and more efficient energy systems is expected to cut global emissions by more than half by 2100, most estimates show we'll need to remove billions of metric tons of carbon dioxide annually by mid-century to keep the climate in check. Carbon removal can come in many different forms, some simple, some technologically advanced. So today, we're going to look at six of the biggest ways scientists are trying to pull greenhouse gases out of the atmosphere. First, forests. This one's a simple one. Trees are probably the most common carbon sink that people are aware of. By the way, a carbon sink is just something that removes CO2 from the air. Forests absorb about 15% of the carbon dioxide generated by burning fossil fuels every year. That's more than 1,500 million metric tons of emissions every year. Photosynthesis removes carbon dioxide naturally, and once trees absorb it, they're especially good at storing it. Expanding, restoring, and managing existing forests more effectively are ways scientists are trying to leverage the power of photosynthesis to convert carbon dioxide in the air into carbon stored in the wood and soil. Every acre of land restored to temperate forests can sequester about three metric tons of CO2 per year. These approaches can be relatively inexpensive and yield cleaner air and water, all while providing a place for you to walk your dog. One of the major challenges to planting trees on a mass scale is to ensure that forest expansion in one area doesn't come at the expense of forests somewhere else. For example, we're forcing farmland to reduce the food supply, which could necessitate converting forests somewhere else, especially in other countries, to farmland. These dynamics make restoring and managing new and existing forests especially challenging. Since I mentioned trees, I'd be remiss not to mention that Mr. Beast and Mark Robert's fundraiser to plant 20 million trees is still ongoing. They've already planted more than 14 million trees, and if you're interested in supporting, go to teamtrees.org, link in the description. The second way to pull emissions involves farms. Soils naturally store carbon, like a lot of it. Surprisingly, the Earth's soil contains four times more carbon than the total stored in all living plants and animals, including those forests we just talked about. There are more than 250 million acres of farmland in the US that's the size of Texas and California combined. But agricultural soils are running a big carbon deficit due to their intensive use. Because of how much farmland there is, even small improvements in farming practices that increase the carbon per acre on farms are hugely impactful. Building soil carbon is even good for farmers and ranchers, since it increases soil health and crop yields. Planting cover crops, those are the crops that cover the ground when fields would otherwise be bare during off seasons or off years, can extend photosynthesis throughout the year. And using compost can improve yields while storing compost carbon content in the soil. Scientists are even working to breed crops with deeper roots, making them more resistant to drought while depositing more carbon into the soil. Number three, bioenergy with carbon capture and storage, otherwise known as BEX. BEX is another way to use photosynthesis to combat climate change, but it's far more complicated than planting trees or managing soils. And it doesn't always work for the climate if it's not done right. BEX is the process of extracting bioenergy from biomass and capturing and storing the carbon, thus removing it from the atmosphere. It's a hard definition to understand, so let's work with the most common example. Energy plants will grow trees or crops. As the plants grow, they'll pull CO2 out of the air. Then, once the plant has grown, carbon is left behind while biomass is extracted for biofuel production. That biofuel can be used to power cars or planes, and the carbon that was left behind can be stored underground or mixed into long-lived products like concrete. So fuel was produced while removing CO2 from the air. As of 2019, five facilities around the world are actively using BEX technologies and are capturing approximately 1.5 million tons of CO2 per year. This technology is currently prohibitively expensive. Research has shown that similar methods could increase both energy generation and CO2 removal by more than 50 times relative to modern-day BEX systems. So the technology does show promise. 4. Direct Air Capture This is probably what most people think of when talking about removing CO2 from the air. Direct air capture is the process of chemically scrubbing carbon dioxide directly from the ambient air. Again, storing it either underground or in long-lived products like concrete. This new technology is not unlike the carbon capture and storage technology employed today at power plants and industrial facilities. It's relatively straightforward to measure and account for the climate benefits of direct air capture, and its potential scale is enormous. But the technology remains costly and energy intensive, but as the energy and technology costs go down and more energy is produced by renewable sources, direct air capture has the potential to take back billions of tons of emissions annually. 5. Sea Water Capture Direct air capture, but for the fishes. Oceans are actually the largest carbon sink on Earth. While the oceans represent a great potential to reduce emissions, when they absorb CO2, it increases the acidity of the sea water. And increasing the acidity of the oceans has its own effects, like destroying coral reefs and delicate ecosystems. But scientists are looking in a ways to scrub CO2 out of the oceans, like we scrub CO2 out of the air. By reducing CO2 concentration in the ocean, the water then draws in more carbon from the air to regain balance. And sea water has a much higher density of CO2 compared to ambient air, which means less work is required to separate it out than in direct air capture. But sea water is also considerably heavier than air, which means more work to move it through any processing facility. The US Navy has already developed a prototype sea water capture device. Because CO2 can be converted to fuel by adding energy, this technology can allow vessels to create their own fuel at sea. Of course, if the captured carbon is converted to fuel and combusted, it just returns to the atmosphere. But this still reduces the need to add new emissions by burning fossil fuels, and future applications of this technology could provide long-term storage for captured carbon. Last but not least, enhanced weathering. Some minerals naturally react with CO2, turning carbon from a gas into a solid. This process is commonly referred to as weathering, and it typically happens very slowly. But scientists are figuring out how to speed up the process. This could mean pumping mineral water, not the kind you buy in stores, from underground deposits to the surface where minerals can react with the air. Another example would be moving air through large deposits of mine tailings, the parts that mines dig up that don't have the ores they're looking for that contain the right mineral composition to absorb CO2. All these technologies have to grapple with how cost-effective and easy to scale they are. The final answer probably won't be just one of them, but a combination of them working together. I hope you enjoyed getting smarter with us today. If you liked this video, consider sharing it with a friend. And remember, there's always more to learn.