<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>topher515</author><text>My understanding is that reforestation, while being wonderful and helpful, simply doesn’t address the scale of the problem.&lt;p&gt;All forests today contain ~200 gigatons of carbon. Humans release ~25 gigatons of carbon per year. So DOUBLING the size of forests on Earth would just absorb 8 years of greenhouse gas emissions.&lt;p&gt;This made no intuitive sense to me until I began to think of the fossil fuels we’ve got underground as representing millions of years of forests “compressed” into oil &amp;#x2F; gas.</text><parent_chain><item><author>jackfoxy</author><text>Stopping and even reversing deforestation is the single most efficient form of CO2 reduction&amp;#x2F;capture we have available.&lt;p&gt;Deforestation rivals fossil fossil fuels for greenhouse gas emissions (up to 30% of anthropic emissions) yet it rarely gets talked about. Could it be because there is no money to be made in halting deforestation?&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.cfr.org&amp;#x2F;backgrounder&amp;#x2F;deforestation-and-greenhouse-gas-emissions&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.cfr.org&amp;#x2F;backgrounder&amp;#x2F;deforestation-and-greenhous...&lt;/a&gt;
&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.nature.com&amp;#x2F;articles&amp;#x2F;ngeo671&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.nature.com&amp;#x2F;articles&amp;#x2F;ngeo671&lt;/a&gt;&lt;p&gt;On the fossil fuel side what we need is a large scale industrial use of CO2 that is not hopelessly energy inefficient. If such a breakthrough happens we could build gas turbine farms at gas fields and pipe the CO2 to industrial centers. Modern gas turbines are the most efficient form of electricity generation. The emissions consist almost entirely of H2O and CO2, some collateral NO2, and trace amounts of other stuff from combusted impurities.</text></item></parent_chain></comment><story><title>What if carbon removal becomes the new Big Oil?</title><url>https://www.economist.com/the-world-if/2020/07/04/what-if-carbon-removal-becomes-the-new-big-oil</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>semi-extrinsic</author><text>&amp;gt; what we need is a large scale industrial use of CO2 that is not hopelessly energy inefficient&lt;p&gt;Unfortunately this is somewhere between hopelessly improbable and impossible, for two reasons:&lt;p&gt;First, our CO2 storage needs are in the tens of gigatonnes per year. At the highest practical storage density of pure CO2, one gigatonne is about 10^9 cubic meters - 400 times the volume of the Hoover Dam. There are simply no existing human product streams that are within even a couple orders of magnitude of being able to absorb that.&lt;p&gt;Second, CO2 is a waste product. Turning it into any other useful product will demand not just the energy gained from burning the fuel, but quite a bit more due to thermodynamic inefficiency.&lt;p&gt;There absolutely ain&amp;#x27;t no free lunch with regards to CO2 capture. It&amp;#x27;s perfectly doable but it&amp;#x27;s a pure cost that should just be government regulated everywhere ASAP.</text><parent_chain><item><author>jackfoxy</author><text>Stopping and even reversing deforestation is the single most efficient form of CO2 reduction&amp;#x2F;capture we have available.&lt;p&gt;Deforestation rivals fossil fossil fuels for greenhouse gas emissions (up to 30% of anthropic emissions) yet it rarely gets talked about. Could it be because there is no money to be made in halting deforestation?&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.cfr.org&amp;#x2F;backgrounder&amp;#x2F;deforestation-and-greenhouse-gas-emissions&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.cfr.org&amp;#x2F;backgrounder&amp;#x2F;deforestation-and-greenhous...&lt;/a&gt;
&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.nature.com&amp;#x2F;articles&amp;#x2F;ngeo671&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.nature.com&amp;#x2F;articles&amp;#x2F;ngeo671&lt;/a&gt;&lt;p&gt;On the fossil fuel side what we need is a large scale industrial use of CO2 that is not hopelessly energy inefficient. If such a breakthrough happens we could build gas turbine farms at gas fields and pipe the CO2 to industrial centers. Modern gas turbines are the most efficient form of electricity generation. The emissions consist almost entirely of H2O and CO2, some collateral NO2, and trace amounts of other stuff from combusted impurities.</text></item></parent_chain></comment><story><title>What if carbon removal becomes the new Big Oil?</title><url>https://www.economist.com/the-world-if/2020/07/04/what-if-carbon-removal-becomes-the-new-big-oil</url></story>