Weekend Reading: Three Climate Attribution and Impacts Posts

For those of us with a long weekend and possibly more time for reading, here are three thoughtful pieces by knowledgeable climate folks.

My personal opinion is that I believe something is going on climate-wise, affected by greenhouse gases, irrigation, changes in surface reflection, and many other things humans do or don’t do (and likely some we are not currently aware of).  I also think that a mix of folks with good intentions and grifters of all kinds have jumped on the climate bandwagon, with varying end results in mind.  And I think that better understanding of the various elements of science and practice around mitigation and adaptation (more light and less heat) will ultimately make our world better, as we jointly confront whatever lies ahead.  And I wonder about the tendency for solutions in this space to become both top-down, and stick-y rather that carrot-y.  This does not build trust IMHO.

1) Ricardo Simonds on his direct experience of the Brazilian flood disaster.  Here are a few tables of interest.. also look for his Katherine Hepburn vs. Walter Brennan analogy, probably particularly meaningful to those of a certain age..

As I wrote,

The cast of characters in a disaster is well established, comprised of components and their associated drivers. Any natural disaster is comprised of three components: the hazard, exposure and vulnerability. Each component in turn is affected, or motivated, by drivers.

I recently posted about flooding in Brazil in May, 2024, that left almost 600,000 people displaced, 77,000 rescued, 800 injured and 169 dead (see official data here). It’s a terrible tragedy that has mobilized the nation.

If the Brazilian landslides were a movie and the disasters causes were personified by actors, the Oscars would nominate best actresses and supporting actors. While the media and science activism overwhelmingly promote climate change at the lead actress in every single weather disaster, many times the lead actor is vulnerability or exposure.

The media always tells you climate change is Katherine “Climate” Hepburn (most lead actress Oscars of all time) when climate is often Walter Brennan (most supporting actor Oscars of all time). Never heard of Brennan? That’s my point.

Here’s a few of the many interesting tables in his post-  for those of you who don’t follow this stuff, Swiss Re is a reinsurance group (insures insurers), and is one of the world’s largest. SCS are “severe convective storms”:

If you’re interested in talking with friends over the weekend about trends and attribution, Ricardo posted this Table 12.12 on page 1856 Chapter 12 of IPPC AR6.  Because Ricardo’s post is about landslides, he circled those, but the whole table is interesting.

The whole piece is worth a read for sure.  Let me know if there’s a paywall, I’m a subscriber to his Substack.

2) Roger Pielke, Jr. is starting a series on extreme events and climate change, which looks to be interesting, including the discussion.

It is now a ubiquitous cultural ritual to blame any and every weather event on climate change. Those hot days? Climate change. That hurricane? Climate change. The flood somewhere that I saw on social media? Climate change.

As he goes through, he wants folks to get more specific and meaningful.  What the stories mean is that “increasing GHGs in the atmosphere have made this event more likely”; but Roger starts back with IPCC definitions.  Maybe it seems like a trivial detail, but short hands for complicated concepts can be misleading.

Climate refers to a “statistical description”1 of the climate system, defined as:

The global system consisting of five major components: the atmosphere, the hydrosphere, the cryosphere, the lithosphere and the biosphere and the interactions between them. The climate system changes in time under the influence of its own internal dynamics and because of external forcings such as volcanic eruptions, solar variations, orbital forcing, and anthropogenic forcings such as the changing composition of the atmosphere and land-use change.

The climate system is complicated, but at a high level, we can get our brain around it (above). There is a deeper discussion to be had about why the climate research community decided that people are not included as part of the “climate system,” but let’s leave that for another day.2

Looking forward to that one.

As to detection, he has an interesting thought experiment.

Also, “deck change” cannot be used to attribute the cause of receiving an ace in a single hand. If you know that you have a stacked deck with one additional ace, then you can say with certainty that the odds of receiving at least one ace in your next hand increased from 14.8% to 15.3%.

Did that increase of 0.5% increase cause the ace to appear in your most recent hand?

After 329 hands, you can be 90% confident that the greater number of aces that you received over those hands than you would have expected from an unstacked deck are due to the addition of the extra ace.

A final point for today — The thought experiment described today is a pure statistical example. Dealing two cards from a deck does not remotely describe how weather occurs on planet Earth.

Weather can be characterized statistically, but weather does not occur as a result of simple statistical processes.8 Weather is the the integrated result of at least: dynamical, thermodynamical, chaotic, societal, biospheric, cryospheric, lithospheric, oceanic, vulcanological, solar, and, yes, stochastic processes.

3) Patrick Brown tries to clarify language about climate change impacts  in this post .

When the IPCC says “decreasing,” (sometimes) they mean in comparison to what otherwise they would have modeled to occur (and given how complex human/agricultural/environmental interactions are,  I would take such models with several grains of salt), not (as we might commonly use the term) decreased from the past.   Decreasing crop yields compared to the past (observable decreases in something measured regularly on this planet) are very different in real life than overall increases with the increase smaller than what might have been without  (modeled) climate change. Now, I am not against the use of models, but they are not the same thing as observations.

This seems like a very important point. Here’s a piece of his post.

Take, for example, the statement, “Climate change is decreasing crop yields.” This could mean that we are seeing crop yields decrease over time, and this trend is being driven by climate change (left side), or it could mean that crop yields are increasing over time, but they would have been increasing faster if the climate wasn’t changing (right side).

So, which is it? For crop yields, the situation is much more like the right side than the left side. However, the IPCC repeatedly states in its reports that climate change is “decreasing” crop yields, misleadingly conveying the message that the situation is more like the left side.

Climate change impacts on agriculture have been calculated to make up the largest negative societal impact of climate change as quantified in the social cost of carbon, while heat impacts on mortality represent the second largest. So, how does the IPCC report on mortality associated with heat? In its technical summary (B.5.3), the IPCC reports that,

“Increasing temperatures and heatwaves have increased mortality and morbidity (very high confidence).”

Most readers will interpret this to mean that heat deaths are increasing relative to the past (they will infer a direction of trend). But only those who read the technical chapters will understand that only a direction of impact is being reported because there you will read that heat deaths are decreasing over time:

“Heat-attributable mortality fractions have declined over time in most countries owing to general improvements in health care systems, increasing prevalence of residential air conditioning, and behavioural changes. These factors, which determine the susceptibility of the population to heat, have predominated over the influence of temperature change.”

This type of conflation is ubiquitous in climate change impact reporting. In addition to crop yields and heat mortality, I have previously drawn attention to this issue in the context of global wildfire, emissions, hunger, and climate-sensitive diseases like malaria.

What Patrick doesn’t mention in this post is that people who deal with observations (like many of us) tend to read something like “climate is decreasing crop yields” and look around and see that in the meaning of “decreased from the past” it doesn’t appear to be true.   Without digging into the technical chapters, we’ll just think “they don’t know what they’re talking about.”  For myself, I have this crazy idea that we should try as much as we can for people observing the real world, and the people modeling it, to try to get on the same page.  What a simple clause to add, “decreased from where it would be modeled to be without climate change.”