{"id":286560,"date":"2023-11-04T20:19:32","date_gmt":"2023-11-04T19:19:32","guid":{"rendered":"https:\/\/climatescience.press\/?p=286560"},"modified":"2023-11-04T20:19:35","modified_gmt":"2023-11-04T19:19:35","slug":"a-major-surprise-nature-study-finds-phasing-out-fossil-fuels-will-lead-to-decades-of-warming","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=286560","title":{"rendered":"A \u2018Major Surprise\u2019 Nature Study Finds Phasing Out Fossil Fuels Will Lead To Decades Of Warming"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

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

Anthropogenic aerosols mask the climate warming caused by greenhouse gases (GHGs). In the absence of observational constraints, large uncertainties plague the estimates of this masking effect. Here we used the abrupt reduction in anthropogenic emissions observed during the COVID-19 societal slow-down to characterize the aerosol masking effect over South Asia.<\/em><\/strong><\/p>\n\n\n\n

\"\"
Measurements during the period 24 March to 31 May.\u00a0a<\/strong>\u00a0Mean Aerosol Optical Depth (AOD) for the period in the years 2007 to 2019.\u00a0b<\/strong>\u00a0Mean AOD for the period in 2020.\u00a0c<\/strong>\u00a0Mean relative change of AOD550 nm<\/sub>\u00a0retrieved using MODerate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua satellite for the period. The black arrows embedded in panels\u00a0a<\/strong>\u00a0and\u00a0b<\/strong>\u00a0represent mean wind vectors for the corresponding period at 700 hPa. The box (red color) in panel\u00a0c<\/strong>\u00a0indicates the region of Indo-Gangetic Plain.\u00a0d<\/strong>\u00a0Mean Top of the Atmosphere (TOA) clear sky flux for the periods in the years 2007 to 2019.\u00a0e<\/strong>\u00a0Mean TOA clear sky flux for the period in 2020.\u00a0f<\/strong>\u00a0Mean Relative change of TOA clear sky flux for the period retrieved using CERES onboard Aqua and Terra satellites.<\/figcaption><\/figure>\n\n\n\n

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

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

By\u00a0Kenneth Richard<\/a>\u00a0on\u00a0<\/em>2. November 2023<\/p>\n\n\n\n

\u201cWe would expect from a 100% switchover from fossil fuels to zero-emission renewables\u2026net radiative heating would increase drastically.\u201d \u2013 Nair et al., 2023<\/strong><\/h4>\n\n\n\n

Using observational data gleaned from COVID-19 lockdowns in South Asia, scientists publishing in a Nature<\/em> journal (Nair et al., 2023<\/a><\/strong>) have now determined the ongoing switch to zero greenhouse gas (GHG) emissions renewables will subsequently lead to a dramatic reduction in climate-cooling aerosol (pollution) emissions. Because aerosol emissions have a relatively greater climate impact by reflecting shortwave radiation, the net effect of transitioning to renewables will be to \u201cdrastically\u201d increase Earth\u2019s temperatures over the coming decades.<\/p>\n\n\n\n

\u201cMitigation strategies focusing on the phase-out of fossil fuels will lead to quick removal of the short-lived aerosols while the longer-lived major greenhouse gases decrease much more slowly, likely resulting in undesired net warming of the climate during a decades-long transition period.\u201d<\/em><\/p>\n\n\n\n

\"\"
Image Source:\u00a0Nair et al., 2023<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

The curtailment of industrial and transport energy use in South Asia during COVID lockdowns (March-May 2020) not only reduced fossil fuel (GHG) emissions, but also the associated aerosol (pollution) emissions that serve to cool the climate by reflecting shortwave radiation.<\/p>\n\n\n\n

Scientists have assessed a ~7% reduction in aerosol emissions during the initial lockdown months induced a ~20 W\/m\u00b2 increase in downwelling solar radiation forcing.<\/p>\n\n\n\n

The magnitude of this reduced-aerosol-emissions climate forcing (~20 W\/m\u00b2 within just a few months) is characterized as a \u201cmajor surprise.\u201d<\/p>\n\n\n\n

To put this into perspective using the conclusions found in Feldman et al., 2015<\/a><\/strong>, this aerosol forcing is about 100 times larger than the clear-sky surface forcing (0.2 W\/m\u00b2) associated with 10 years of CO2 increases (22 ppm).<\/p>\n\n\n\n

The switch to 100% renewables, or the phasing out of fossil fuel energy sources, has the (unintended) net effect of causing decades of warming. This is the opposite of mitigation policy intentions.<\/p>\n\n\n\n

\n\n\n\n