When hydrocarbon fuels i. During combustion or burning, carbon from fossil fuels combine with oxygen in the air to form carbon dioxide and water vapor. These natural hydrocarbon fuels come from once-living organisms and are made from carbon and hydrogen, which release carbon dioxide and water when they burn. Not only does the burning of forests release carbon dioxide, but deforestation can also affects the level of carbon dioxide.
Trees reduce the amount of carbon dioxide from the atmosphere during the process of photosynthesis, so fewer trees means more carbon dioxide left in the atmosphere. NPR's Robert Krulwich and Odd Todd, in partnership with Wild Chronicles, present an animated cartoon series on the atom at the heart of global warming: carbon. In episode 3: If you break a carbon bond -- presto! Skip to Main Content Area. Home About Resources References.
Causes of Climate Change. Without it, our planet would be inhospitably cold. However, a gradual increase in CO 2 concentrations in Earth's atmosphere is helping to drive global warming, threatening to disrupt our planet's climate as average global temperatures gradually rise. Carbon dioxide is the fourth most abundant component of dry air. It has a concentration of about ppmv parts per million by volume in Earth's atmosphere.
Scientists estimate that before human industrial activity, CO 2 concentration was around ppmv. Atmospheric carbon dioxide concentrations have varied substantially in the pre-human history of our planet, and have had profound impacts on global temperatures in the past. Carbon dioxide plays a key role in Earth's carbon cycle , the set of processes that cycle carbon in many forms throughout our environment. Volcanic outgassing and wildfires are two significant natural sources of CO 2 in Earth's atmosphere.
Respiration, the process by which organisms liberate energy from food, emits carbon dioxide. When you exhale, it is carbon dioxide amongst other gases that you breathe out. Combustion, whether in the guise of wildfires, as a result of slash-and-burn agricultural practices, or in internal combustion engines, produces carbon dioxide. Photosynthesis, the biochemical process by which plants and some microbes create food, uses up carbon dioxide.
And there will be periods of surplus solar energy that need to be soaked up, energy that might otherwise have gone wasted. To be clear: the future is electrification. When it comes to decarbonization, it is always better to electrify the end uses of energy — to use the electricity directly, rather than losing a large fraction of it to conversions — but even under optimistic scenarios, there are going to be sectors that are difficult to electrify.
Carbon-neutral liquid fuels for sectors that are difficult to decarbonize are both a large market and a key piece of the decarbonization puzzle. Using various catalysts, CO2 can be made into a variety of chemical intermediaries — materials that then serve as feedstocks in other industrial processes, like methanol, syngas, and formic acid.
CO2 can also be transformed by catalysts into polymers, the precursors for plastics, adhesives, and pharmaceuticals. For now, CO2 derived polymers are quite expensive, but plastics are another potentially substantial market — they represent a growing fraction of demand for liquid fossil fuels. And they have a lifespan of decades to centuries, so they present some potential for CO2s.
Currently, only a few chemical applications of CO2 are commercialized at scale, including the production of urea and polycarbonate polyols. Captured CO2 can be used to accelerate the growth of algae , which has the capacity to absorb much more of it, much faster, than any other source of biomass. And algae is uniquely useful. It can serve as feedstock for food, biofuels, plastics, and even carbon fiber see No.
CO2 can be be made into high-performance materials — carbon composites, carbon fiber, graphene — that could conceivably substitute for a whole range of materials, from metals to concrete. They are already used in high-end applications like the Boeing Dreamliner and some sports cars. But as they become cheaper, there is almost no ceiling to the market.
To take just one example, think of substituting carbon nanotubes for copper in electricity wiring. Thanks to Adam Siegel for pointing out this idea. Virtually every application of electricity, from the space station to electric vehicles to household appliances, would benefit from lighter-weight wiring that conducts better.
If carbon-based materials could be substituted for steel on any real scale, it could mean billions of tons of reduced emissions, not to mention effectively permanent carbon sequestration. Of course, this kind of materials research is still in its early stages and will take some technological breakthroughs to bring down costs enough to begin displacing other materials at scale.
For now, carbon materials are getting a foothold in boutique markets. So the chart below contains some extraneous information for our purposes.
There are two scenarios, reflecting the low end and high end of projections. Those below that line are already competitive. Those above the line would need a commensurate subsidy of some kind to compete. The width of the bars indicate the amount of CO2 the technology could utilize annually by based on projections and expert opinion.
And the color of a bar indicates its TRL. Based on the optimistic high scenario, a few of the chemical pathways polyol, urea, and methanol are already cost-competitive, though their potential for CO2 use is relatively small, close to a gigaton cumulatively. The concrete pathways aggregates and curing are fairly close to cost-competitive and curing in particular has fairly large potential, especially when you consider that its CO2 counts twice, once as emission reductions, once as permanent storage.
Troublingly, the industrial CCU technology pathways with the most total potential to use CO2 are the most expensive relative to incumbents. Together, synthetic liquid fuels methanol, methane, dimethyl ether, and Fischer—Tropsch fuels could use over 4 gigatons of CO2 a year by By way of comparison, global CO2 emissions in were about 37 gigatons.
All those are individually difficult to predict; sussing out how they might interact through is a game of educated guessing.
It not only projected how CCU technologies might scale under business as usual, but also how they might scale if the policy recommendations in the roadmap are followed. Again, fuels and aggregates show enormous potential, growing ten- or twenty-fold more under good policy. The more we can use, the less we will emit.
How should policymakers approach CCU technologies? I will address those questions in my next post. Our mission has never been more vital than it is in this moment: to empower through understanding. Financial contributions from our readers are a critical part of supporting our resource-intensive work and help us keep our journalism free for all. Please consider making a contribution to Vox today to help us keep our work free for all.
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