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<p><b>Recent data shows progress is too slow. To keep below two degrees, we will need to dramatically reduce current emissions and simultaneously remove 10-15 gigatons of CO<sub>2</sub>/yr from the atmosphere by 2050 and scale that to about 20+ gigatons annually by 2100. Depending on how quickly we reduce emissions, the amount we need to remove from the atmosphere scales proportionally.</b></p><p>Greenhouse gas emissions are described in units of tons. It’s hard to think about how much “a ton of gas” really is -- this is how big, at surface temperature and pressure. Here’s an animated video visualizing a bunch of these one-ton balls in New York City.</p> | <p><b>Recent data shows progress is too slow. To keep below two degrees, we will need to dramatically reduce current emissions and simultaneously remove 10-15 gigatons of CO<sub>2</sub>/yr from the atmosphere by 2050 and scale that to about 20+ gigatons annually by 2100. Depending on how quickly we reduce emissions, the amount we need to remove from the atmosphere scales proportionally.</b></p><p>Greenhouse gas emissions are described in units of tons. It’s hard to think about how much “a ton of gas” really is -- this is how big, at surface temperature and pressure. Here’s an animated video visualizing a bunch of these one-ton balls in New York City.</p> | ||
<HTML><iframe width="100%" height="315" src="https://www.youtube.com/embed/DtqSIplGXOA" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></HTML><p>You may also hear people talk about “''400 parts per million CO<sub>2</sub>''” or similar. This maps directly to the amount of gas emitted: when emissions mix into the atmosphere, we reference concentrations of the emitted gas as a portion of the atmosphere. This is like stirring sugar into a cup of coffee. For every million parts atmosphere there are 400 parts ''CO<sub>2</sub>'' this proportion has been rising steadily exactly since the industrial revolution...</p><p><html><iframe src="https://ourworldindata.org/grapher/co2-concentration-long-term" style="width: 100%; height: 600px; border: 0px none;"></iframe></html></p><hr><h1 id="basic-intro-to-units-and-measurement">Other greenhouse gases</h1><p>Greenhouse gases are released when stuff is burnt as well as the product of other chemical reactions in industry. Generally, we’re talking about mostly carbon dioxide (<b>CO<sub>2</sub></b>), methane (natural gas) (<b>CH<sub>4</sub></b>), and nitrous oxide (<b>N<sub>2</sub>O</b>). N<sub>2</sub>O and CH<sub>4</sub> are more potent greenhouse gases, but they occur in an order of magnitude less quantity than CO<sub>2</sub>, so removing them is generally much harder. Methane also has a much shorter half life in the atmosphere than CO<sub>2</sub>.</p><h1 id="do-we-really-need-to-remove-co2">Do we really need to remove CO<sub>2</sub>?</h1><p>In the 90s, negative emissions were not [[wikipedia:Overton_window|mainstream]] apart from early research by [[wikipedia:David_Keith_(scientist)|David Keith]], [[wikipedia:Klaus_Lackner|Klaus Lackner]], and others.</p><p>There was some combination of optimism that the problem wasn’t so bad, that the world would decarbonize at a sufficient rate that negative emissions wouldn’t be necessary, and that a policy framework would force action (large scale carbon price/cap and trade, which still doesn’t exist worldwide). This was all combined with fears that negative emissions present a moral hazard by giving ourselves an “out” for crucial emissions reduction work. </p><p>In an attempt to hit a 2 degree warming target, the [https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement Paris agreement] calls on countries to set “Nationally Determined Contributions”, or [https://unfccc.int/process-and-meetings/the-paris-agreement/nationally-determined-contributions-ndcs NDCs] - commitments to a specific amount of emissions reduction over the coming decades. <b>But these commitments are not even close to enough:</b></p> | <HTML><iframe width="100%" height="315" src="https://www.youtube.com/embed/DtqSIplGXOA" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe></HTML><p>You may also hear people talk about “''400 parts per million CO<sub>2</sub>''” or similar. This maps directly to the amount of gas emitted: when emissions mix into the atmosphere, we reference concentrations of the emitted gas as a portion of the atmosphere. This is like stirring sugar into a cup of coffee. For every million parts atmosphere there are 400 parts ''CO<sub>2</sub>'' this proportion has been rising steadily exactly since the industrial revolution...</p><p><html><iframe src="https://ourworldindata.org/grapher/co2-concentration-long-term" style="width: 100%; height: 600px; border: 0px none;"></iframe></html></p><hr><h1 id="basic-intro-to-units-and-measurement">Other greenhouse gases</h1><p>Greenhouse gases are released when stuff is burnt as well as the product of other chemical reactions in industry. Generally, we’re talking about mostly carbon dioxide (<b>CO<sub>2</sub></b>), methane (natural gas) (<b>CH<sub>4</sub></b>), and nitrous oxide (<b>N<sub>2</sub>O</b>). N<sub>2</sub>O and CH<sub>4</sub> are more potent greenhouse gases, but they occur in an order of magnitude less quantity than CO<sub>2</sub>, so removing them is generally much harder. Methane also has a much shorter half life in the atmosphere than CO<sub>2</sub>.</p><h1 id="do-we-really-need-to-remove-co2">Do we really need to remove CO<sub>2</sub>?</h1><p>In the 90s, negative emissions were not [[wikipedia:Overton_window|mainstream]] apart from early research by [[wikipedia:David_Keith_(scientist)|David Keith]], [[wikipedia:Klaus_Lackner|Klaus Lackner]], and others.</p><p>There was some combination of optimism that the problem wasn’t so bad, that the world would decarbonize at a sufficient rate that negative emissions wouldn’t be necessary, and that a policy framework would force action (large scale carbon price/cap and trade, which still doesn’t exist worldwide). This was all combined with fears that negative emissions present a moral hazard by giving ourselves an “out” for crucial emissions reduction work. </p><p>In an attempt to hit a 2 degree warming target, the [https://unfccc.int/process-and-meetings/the-paris-agreement/the-paris-agreement Paris agreement] calls on countries to set “Nationally Determined Contributions”, or [https://unfccc.int/process-and-meetings/the-paris-agreement/nationally-determined-contributions-ndcs NDCs] - commitments to a specific amount of emissions reduction over the coming decades. <b>But these commitments are not even close to enough:</b></p> | ||
<HTML><iframe scrolling="no" frameborder="0" marginheight="0px" marginwidth="0px" style="background: #fff; display: initial; margin: 0 auto;" src="https://cbhighcharts2019.s3.eu-west-2.amazonaws.com/UNEP+Emissions+Gap/emissions_gap.html" width="100%" height="600px"></iframe></HTML> | |||
<h4 id="there-are-two-complementary-scary-things-about-this-chart-">There are two complementary scary things about this chart:</h4><ul><li>All existing Paris commitments (“NDCs” in the above figure) don’t get us even close to a 2 degree trajectory</li><li>Countries are <a href="https://climateactiontracker.org/countries/">not even close to on track to hit even these commitments</a>. This is an incredible collective action problem — each individual country faces minimal/zero “official” consequences for failing to do so.</li></ul><h3 id="here-s-what-the-emissions-gap-looks-like-for-a-1-5-degree-target-source-">Here’s what the <a href="https://www.unenvironment.org/interactive/emissions-gap-report/2019/">emissions gap</a> looks like for a 1.5 degree target (<a href="https://www.carbonbrief.org/unep-1-5c-climate-target-slipping-out-of-reach">source</a>):</h3><!--kg-card-begin: html--> | |||
<iframe scrolling="no" frameborder="0" marginheight="0px" marginwidth="0px" style="background: #fff; display: initial; margin: 0 auto;" src="https://cbhighcharts2019.s3.eu-west-2.amazonaws.com/UNEP+Emissions+Gap/peaking_year_15c.html" width="100%" height="500px"></iframe><!--kg-card-end: html--><h3 id="and-for-a-2-degree-target-source-">And for a 2 degree target (<a href="https://www.carbonbrief.org/unep-1-5c-climate-target-slipping-out-of-reach">source</a>):</h3><!--kg-card-begin: html--> | <iframe scrolling="no" frameborder="0" marginheight="0px" marginwidth="0px" style="background: #fff; display: initial; margin: 0 auto;" src="https://cbhighcharts2019.s3.eu-west-2.amazonaws.com/UNEP+Emissions+Gap/peaking_year_15c.html" width="100%" height="500px"></iframe><!--kg-card-end: html--><h3 id="and-for-a-2-degree-target-source-">And for a 2 degree target (<a href="https://www.carbonbrief.org/unep-1-5c-climate-target-slipping-out-of-reach">source</a>):</h3><!--kg-card-begin: html--> | ||