So many factors, some of which are hardly yet known, affect the rise and fall of planetary temperatures that it is certainly possible that tinkering on one end has the opposite of the intended effect. Watts Up With That points to one example possibly attributable to something called IMO 2020, which has severely reduced sulphur emissions from shipping fuel starting in 2020:
The world of climate science is in shock following extraordinary findings from a team of high-powered NASA scientists that suggest most of the recent global temperature increases are due to the introduction of draconian fuel shipping regulations designed to help prevent global warming. The fantasy world of Net Zero is of course full of unintended consequences, but it is claimed that the abrupt 80% cut in sulphur dioxide emissions from international shipping in 2020 has accounted for 80% of global warming since the turn of the decade.
The news is likely to cause considerable concern among the mainstream climate hoaxers in media, academia and politics. They have had a field day of late by pointing to rises in temperature as evidence for their evidence-free prediction that the climate is in danger of imminent collapse... The science behind the NASA findings, which have been published in Nature, is simple. Fewer fuel particles injected into the atmosphere reduce cloud droplet density and this leads to clouds that reflect less solar radiation back into space.
In the words of the NASA scientists who observed the ironic effect:
While IMO 2020 is intended to benefit public health by decreasing aerosol loading, this decrease in aerosols can temporarily accelerate global warming by dimming clouds across the global oceans. IMO 2020 took effect in a short period of time and likely has global impact... Observations of ship-tracks suggest that... a regulation intended to reduce pollution had collateral effects on cloud microphysics.
Of course, the hoaxers aren't going to take this lying down:
Climate activists at the Potsdam Institute for Climate Impact say the observation period is too short, and man-made greenhouse gases continue to play the decisive role in climate change... [Still] the IPCC promotes the view that almost all climate change since around 1900 is caused by the activities of humans. This unproven opinion looks shakier by the day.
What’s not scientific is claiming anything about the climate is "settled" and that panicked, draconian measures have to be instituted immediately or else we're all doomed.
Article tags: climate alarmism, Climate Warming, IPCC, NASA, Sulfur emissions
Water vapor is a potent GHG. NOAA scrubbed its site on any mention of Hunga-Tonga volcanic eruption on global climate.
Geophys Res Lett. 2022 Jul 16; 49(13): e2022GL099381.
Published online 2022 Jul 1. doi: 10.1029/2022GL099381
PMCID: PMC9285945
PMID: 35865735
The Hunga Tonga‐Hunga Ha'apai Hydration of the Stratosphere
L. Millán, 1 M. L. Santee, 1 A. Lambert, 1 N. J. Livesey, 1 F. Werner, 1 M. J. Schwartz, 1 H. C. Pumphrey, 2 G. L. Manney, 3 , 4 Y. Wang, 1 , 5 H. Su, 1 L. Wu, 1 W. G. Read, 1 and L. Froidevaux 1
Abstract
Following the 15 January 2022 Hunga Tonga‐Hunga Ha'apai eruption, several trace gases measured by the Aura Microwave Limb Sounder (MLS) displayed anomalous stratospheric values. Trajectories and radiance simulations confirm that the H2O, SO2, and HCl enhancements were injected by the eruption. In comparison with those from previous eruptions, the SO2 and HCl mass injections were unexceptional, although they reached higher altitudes. In contrast, the H2O injection was unprecedented in both magnitude (far exceeding any previous values in the 17‐year MLS record) and altitude (penetrating into the mesosphere). We estimate the mass of H2O injected into the stratosphere to be 146 ± 5 Tg, or ∼10% of the stratospheric burden. It may take several years for the H2O plume to dissipate. This eruption could impact climate not through surface cooling due to sulfate aerosols, but rather through surface warming due to the radiative forcing from the excess stratospheric H2O.
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571760/
Introduction
Water vapor in the upper troposphere and lower stratosphere (UTLS) plays an influential role in determining the Earth’s climate. Even small variations in the abundance of UTLS water vapor can significantly modulate the flux of outgoing long-wave radiation, prompting responsive changes in global surface temperatures. Solomon et al. [2010] demonstrated that the rapid 10% drop in UTLS water vapor near the end of 2000 [Randel et al., 2006] reduced the global surface warming from long-lived greenhouse gases and aerosols by 25% during 2000–2009. This sensitive connection with climate dictates that UTLS water vapor be closely monitored for changes, especially those that may result from our warming planet.