{"id":296030,"date":"2024-01-16T13:39:57","date_gmt":"2024-01-16T12:39:57","guid":{"rendered":"https:\/\/climatescience.press\/?p=296030"},"modified":"2024-01-16T13:40:00","modified_gmt":"2024-01-16T12:40:00","slug":"new-research-says-doubling-co2-leads-to-a-sometimes-negative-greenhouse-effect","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=296030","title":{"rendered":"New Research Says Doubling CO2 Leads To A \u2018Sometimes\u2019 Negative Greenhouse Effect"},"content":{"rendered":"\n
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From NoTricksZone<\/a><\/p>\n\n\n\n

By Kenneth Richard<\/a> on 15. January 2024<\/p>\n\n\n\n

\u201cNegative TOA [top of atmosphere] forcing of CO2 increase also happens outside of Antarctica. The Arctic sometimes exhibits strong negative CO2 forcing. This phenomenon even occurs in the tropics and mid-latitudes\u2026\u201d \u2013 Chen et al., 2024<\/strong><\/h4>\n\n\n\n

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It has previously been reported that as CO2 increases from 380 ppm to 1000 ppm, the CO2 greenhouse effect is negative (-2.9 W\/m\u00b2) over Antarctica, or that CO2 \u201cincreases radiative cooling\u201d there (Schmith\u00fcsen et al., 2015<\/a><\/strong>).<\/p>\n\n\n\n

Also, the CO2 greenhouse effect is as \u201ccomparatively weak\u201d (hovering around 0 W\/m\u00b2) over Greenland as it is over Antarctica, but it is not negative there, as it is \u201cinvariably\u201d above 0 W\/m\u00b2 in the Arctic. In other words, there is no such thing as a CO2-enhanced \u201cpolar amplification\u201d at locations where it is commonly claimed CO2 is causing catastrophic ice melt.<\/p>\n\n\n

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Image Source:\u00a0Schmith\u00fcsen et al., 2015<\/a><\/strong><\/figcaption><\/figure>\n<\/div>\n\n\n

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But new research (Chen et al., 2024<\/a><\/strong>) indicates when CO2 increases from 380 to 760 ppm the negative (below 0 W\/m\u00b2) greenhouse effect of CO2 can not only be found over Antarctica, but \u201csometimes\u201d in the Arctic (Greenland especially), the tropics, and mid-latitudes as well.<\/p>\n\n\n\n

The bar graphs and colorized chart in the paper show that as CO2 doubles (760 ppm) it only produces a radiative forcing differential ranging between -1.5 W\/m\u00b2 to about +3 W\/m\u00b2.<\/p>\n\n\n\n

In contrast, the authors identify cloud radiative forcing (CRE, cloud radiative effect) contributing ~120 W\/m\u00b2 (50-190 W\/m\u00b2) to greenhouse effect enhancement. In other words, the greenhouse effect of clouds is two orders of magnitude larger than from the greenhouse effect from doubled CO2.<\/p>\n\n\n\n

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This is consistent with the assessment that CO2 must be increased 100-fold (to ~40,000 ppm) to begin to revival the greenhouse effect of clouds (Ramanathan et al., 1989<\/a><\/strong>). Given analyses like these, it is rather puzzling that it is believed CO2 is\u00a0the<\/em>\u00a0climate driver.<\/p>\n\n\n\n

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Image Source:\u00a0Ramanathan et al., 1989<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n
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