{"id":283150,"date":"2023-10-13T14:43:08","date_gmt":"2023-10-13T12:43:08","guid":{"rendered":"https:\/\/climatescience.press\/?p=283150"},"modified":"2023-10-13T14:43:12","modified_gmt":"2023-10-13T12:43:12","slug":"new-study-upends-modeling-finds-earths-rocks-are-a-net-source-of-co2-rivaling-volcanic-emissions","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=283150","title":{"rendered":"New Study Upends Modeling, Finds Earth\u2019s Rocks Are A Net Source Of CO2 Rivaling Volcanic Emissions"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

New research has overturned the traditional view that natural rock weathering acts as a CO2<\/sub>\u00a0sink that removes CO2\u00a0<\/sub>from the atmosphere.<\/strong><\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

From NoTricksZone<\/a><\/p>\n\n\n\n

By\u00a0Kenneth Richard<\/a>\u00a0on\u00a0<\/em>12. October 2023<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

For decades rock weathering has been thought to be a net sink in carbon budget models. New research finds rock emissions are a large net source of CO2 to the atmosphere.<\/strong><\/p>\n\n\n\n

A few years ago Buesseler et al., 2020<\/a><\/strong> discovered that all of the climate modelers\u2019 previous estimates of global ocean carbon uptake are substantially wrong because they were measuring from the fixed \u201ccanonical fixed 150-m depth.\u201d The alleged new-and-improved way to assess carbon uptake is from much shallower depths: the euphotic zone (Ez). This is the section of the upper ocean layer that sunlight is able to penetrate, and it can \u201cvary from less than 20 m to almost 200 m\u201d in depth.<\/p>\n\n\n\n

When the variable Ez depth is used to estimate carbon absorption versus export, the absorption estimate changes by more than a factor of 2, from 2.8 petagrams of carbon (PgC) per year to 5.7.<\/p>\n\n\n\n

\"\"
Image Source:\u00a0Buesseler et al., 2020<\/a><\/strong>\u00a0and\u00a0press release<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

Now, new research reverses the decades-long assumption that rocks exposed to the air absorb CO2 from the atmosphere. Instead, weather-exposed rocks \u201cact as a large CO2 source,\u201d as they release \u201cas much carbon dioxide as the world\u2019s volcanoes.\u201d Rock weathering as a net source of CO2 is thus \u201cnot captured in climate models.\u201d<\/p>\n\n\n\n

\"\"
Image Source:\u00a0AAAS<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

About 5 years ago it was discovered that modeled estimates of CO2 emissions from volcanoes are 10 times smaller than actual measurements indicate (Illyinskaya et al., 2018<\/a><\/strong>).<\/p>\n\n\n\n

\"\"
Image Source:\u00a0Illyinskaya et al., 2018<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

Another 2018 study (Gray et al.<\/a>, <\/strong>with a Physics Today<\/a><\/em><\/strong> press release) estimated the carbon uptake for the Southern Ocean. But instead of using the traditional ship-based measurement, the authors utilized biochemical floats. The results upended decades of modeling.<\/p>\n\n\n\n

Instead of absorbing close to 1 petagram of carbon (PgC) per year, the Southern Ocean is barely even a carbon sink at all \u2013 just 0.08 PgC of yearly absorption (with a ~14 times larger uncertainty range, \u00b10.55 PgC\/year). Large regions of the Southern Ocean near Antarctica are now considered a net source of CO2 to the atmosphere.<\/p>\n\n\n\n

In other words, when estimates are float-based rather than ship-based, one estimate can be more than 10 times different than another.<\/p>\n\n\n\n

\"\"
Image Source:\u00a0Physics Today<\/em><\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

These wildly varying results and consequent large uncertainties underscore just how guess-based carbon budget modeled estimates are.<\/p>\n\n\n\n

—————————————————————————————————————————————–<\/p>\n\n\n\n