In a study conducted by
McGill University researchers, it was found that there is a small decrease in local
warming when there is reduced cloud cover.
This happens from a decrease in longwave radiation being deflected back
to the surface by clouds, in an atmospheric feedback loop. Longwave radiation comes from sunlight
reaching the earth’s surface, being deflected into the atmosphere, and in many
cases being deflected again back to the surface by clouds, trapping it in the
space between cloud cover and the ground.
Thus, a reduction in cloud cover results in more longwave radiation
leaving the surface, resulting in a minor offsetting of the more general global
warming trend. The research team used
radiative instruments in their study, including Atmospheric Emitted Radiance
Interferometer (AERI), remote sensing, climate models, and their own “optimal
spectral fingerprinting” technique to study the effects of longwave radiation
on climate. An important consequence,
the researchers believe, is that the surface would warm even faster without
this mitigating effect. They suggest
this offset does not entirely reduce the impact of global warming; it merely
reduces the warming rate to a small degree.
The
title of the news article “Clouds Have Surprising Effect on Surface Warming”
provides no detail about the findings.
The title of the scholarly article “Clouds reduce downwelling longwave
radiation over land in a warming climate” is more specific to include
the impact of clouds on longwave radiation and how it applies to global
warming. The research article does a
better job explaining the conclusion with the assistance of other studies and
not entirely its own, while the news article boldly states that only the McGill
researchers discovered it. There weren’t
any details in the news article about “optical spectral fingerprinting”, which
apparently is a new method invented by one of the researchers. This to me is an omission of significant
detail because the lay reader is likely unfamiliar with such a new method. Finally, the news article omits a key
statistical method from the research article; that they used linear regression
to determine which variable(s) were doing the most mitigating of longwave
radiation. To give the news article
credit, it was consistent with the message and main points of the research
article. Though the study was only done
locally- in the southern Great Plains- both articles concluded that it is a
global phenomenon occurring at a non-specific site. Both articles were also consistent in asserting
that this information will improve predictions about climate change. The research group for the scholarly article
is run by Professor John Gyakum at McGill University and does not appear to
show any bias.
I
believe the title of the news article is intentionally vague to serve as
clickbait. People naturally want to know
what the “surprising effect” of anything is.
I am satisfied that the news article agrees with the main points of the
research article, but not with the lack of details provided, and especially
with the failure to mention other studies that point to the same conclusion. It shows a lack of integrity on the part of
the news publisher; that they would minimize the amount of writing in the
interest of generating more clicks and shares on social media. Perhaps they are trying to make the article
more efficient for their readers, but it comes off as lazy and disingenuous.
News article:
McGill University. (2025,
January 15). Clouds have a surprising effect on surface warming. ScienceDaily.
Retrieved January 20, 2025 from www.sciencedaily.com/releases/2025/01/250115165341.htm
Scholarly article:
Liu, L., Huang, Y. &
Gyakum, J.R. Clouds reduce downwelling longwave radiation over land in a
warming climate. Nature (2025). https://doi.org/10.1038/s41586-024-08323-x
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