Climate Expert: What The Media Won’t Tell You About Floods

According to a poll conducted in late 2021, “Ninety-five percent of Americans believe the spread of misinformation is a problem.”

As I have documented for more than a decade, public representations in the major media of the relationship between climate change and disasters are chock full of misinformation. [bold, links added]

What makes this issue fairly unique is the role played by journalists and some scientists in helping to spread that misinformation, while ignoring peer-reviewed science and consensus assessments.

In Part 4 of this ongoing series titled “What the media won’t tell you about…”, I focus on climate change and floods. Earlier posts in this series focused on:

• Hurricanes
• U.S. heat waves
• Western and Central and European drought

Today’s post is organized into three sections:

(1) What do the most recent reports of the Intergovernmental Panel on Climate Change (IPCC) and U.S. National Climate Assessment (NCA) say about floods;

(2) Trends in the societal impacts of flooding, specifically damage, deaths, and people affected, and;

(3) What the most recent literature says about flooding and its impacts on the future?

What the IPCC and U.S. NCA say about flooding

The IPCC is unequivocal in its conclusions about the relationship between floods and climate change (for a quick primer on detection and attribution as used by the IPCC, have a quick look here):

In summary, there is low confidence in the human influence on the changes in high river flows on the global scale. In general, there is low confidence in attributing changes in the probability or magnitude of flood events to human influence because of a limited number of studies, differences in the results of these studies and large modelling uncertainties.

That means that the IPCC does not have confidence in overall trends in flooding.

It also means that the IPCC similarly does not have confidence that the “probability or magnitude of flood events” can be attributed to climate change.

The IPCC could not be more clear.

Let’s contrast what the IPCC says with a few recent media reports:

• NPR: “How climate change drives inland floods” (shown also at the top of this post)
• The Washington Post: “both drought and flooding are closely tied to human-driven warming”
• New York Times: “When it comes to river floods, climate change is likely exacerbating the frequency and intensity of the extreme flood events”

The three articles have in common a common feature: each ignored the consensus conclusions of the most recent IPCC report.

The New York Times article is particularly egregious in that the cited passage alleging increasing floods does not actually refer to historical observations, but instead to a study projecting future flooding under the infamous RCP8.5 scenario.

Don’t get me started.

The IPCC — which deserves a lot of kudos for this — explicitly warned against associating increases in extreme rainfall (even if attributed to human causes) with flooding caused by climate change:

Attributing changes in heavy precipitation to anthropogenic activities (Section 11.4.4) cannot be readily translated to attributing changes in floods to human activities, because precipitation is only one of the multiple factors, albeit an important one, that affect floods.

The lack of a direct relationship between extreme precipitation and flooding is something that we were among the first to document empirically more than 20 years ago.

And there is more that may be surprising — in the United States, according to the U.S. NCA, it is not even appropriate to attribute an increase in extreme precipitation to climate change (emphasis added in below).

The complex mix of processes complicates the formal attribution of observed flooding trends to anthropogenic climate change and suggests that additional scientific rigor is needed in flood attribution studies. As noted above, precipitation increases have been found to strongly influence changes in flood statistics.

However, in U.S. regions, no formal attribution of precipitation changes to anthropogenic forcing has been made so far, so indirect attribution of flooding changes is not possible. Hence, no formal attribution of observed flooding changes to anthropogenic forcing has been claimed.

The casual attribution of heavy rains to climate change and then by extension any associated flooding to climate change is like catnip for the media (see here and here).

However, such claims are not supported by consensus scientific assessments.

The bottom line from these recent consensus assessments is clear:

• Flooding has variously increased and decreased over different time periods in different places around the world (including the U.S.), but no overall trend has been detected.
• In the absence of an overall increase (or decrease), there is no trend to be explained, hence attribution of flooding to climate change has not been achieved.

Finally, despite evidence for increases (in some places) in extreme precipitation attributable to climate change, the IPCC is explicit that this cannot be extended to flooding.

And in the U.S., the NCA is explicit that attribution to climate change of detected increases in extreme precipitation in some regions is “not possible.”

Read rest at The Honest Broker