I read articles on the Guardian’s website most days, with a view to enjoying and receiving benefit from some occasionally excellent journalism, but mostly to see what’s going on in the world of those who believe we are facing a “climate crisis”. As a result, I think I have identified a fairly stale but stable format, namely – find places in the world that are facing problems, seek desperately for reasons why those problems can be attributed to the said “climate crisis”, then produce an article with a suitably alarming headline.

As the format continues so, I suppose, will I find myself writing pieces that seek to debunk the claims. I have already written “The Gambia Gambit”ⁱ, in which I hope I succeeded in demonstrating that the climate crisis facing The Gambia is no such thing. And then there was “Volte-Face”ⁱⁱ, in which I expressed bewilderment at how human-made climate change can apparently make drought worse and result in the shrinking of Lake Turkana, only for human-induced climate change then to make heavy rainfall worse and result in the flooding of Lake Turkana. Today, though, we turn to a different continent.

Sun sets on Mexico’s paradise beaches as climate crisis hits home

Sufficiently alarming, do you think? That was the headline to an articleⁱⁱⁱ that appeared in the Guardian today, 14^th March 2022. In case the headline didn’t do the job adequately, the sub-heading tried to ensure that the message was clear: “Rising sea levels and fierce storms threaten Quintana Roo’s coastline, and with it the ribbon of beach resorts and timeshares”.

What a gloomy story. From “the increasingly unmanageable quantities of seaweed washing up on the beach”, to “a bigger, existential concern.” Yes, you guessed – climate change. “Rises in sea level driven by – not just climate change, but by – “the climate crisis”.

Beaches are disappearing, and some are only maintained artificially with sand dredged from the seabed. Often they are little more than strips of sand, no wider than a dirt road. Sometimes the strand has completely vanished, leaving waves breaking against the walls of swimming pools, restaurants and houses.

And as if that isn’t enough:

Hurricanes are expected to increase in intensity due to higher ocean temperatures, leading to storm surges and exacerbating beach erosion. In 2005, Cancún lost large swaths of an eight-mile beach after Hurricane Wilma, which were later artificially restored, and then hit again by Hurricane Dean two years later.

Finally:

Algal blooms have also plagued the coast of the Riviera Maya, a phenomenon scientists have linked to warming sea temperatures. The beachfront along the coast is frequentlylined with mounds of rotting black seaweed. In Tulum, the seaweed is often stacked high in piles with workers shovelling it on to wheelbarrows on the shore and hotel owners despairing over where to put it all.

Let’s look at that last claim first.

Sargassum: The biggest seaweed bloom in the world

So says the headline to a BBC article^iv that appeared on 4^th July 2019. The article confirms that the biggest seawood bloom in the world stretched from West Africa to the Gulf of Mexico, and has inundated beaches, causing an environmental nuisance. But what has caused this strange recent phenomenon?

Deforestation and fertiliser use are among the factors thought to be driving the growth.

Of course, being the BBC, we are also told:

…”This is all ultimately related to climate change because it affects precipitation and ocean circulation and even human activities, but what we’ve shown is that these blooms do not occur because of increased water temperature,” said Dr Hu.

However, no link between climate change and the blooms is offered, merely a claim that “This is all ultimately related to climate change”, but without an explanation. And, crucially, while the Guardian says it is “a phenomenon scientists have linked to warming sea temperatures”, the BBC assures us that “these blooms do not occur because of increased water temperature”. So much for settled science.

In fairness, climate change is put forward (it seems it’s obligatory) by researchers who say more study and funding is needed to get to the bottom of the issue, but it’s a relatively minor contributory factor, if it’s a factor at all:

The influxes of the past decade seem to have originated along Brazil’s Atlantic coast, not in the Sargasso Sea. Large amounts of fertilizer flow into the Amazon River and then to the ocean from industrial-scale agriculture and ranches. Nutrients also pour into the Gulf of Mexico from the Mississippi River. Climate change-driven downpours increase runoff.

Saharan dust clouds that extend for thousands of miles across the Atlantic Ocean have also contributed to this explosion of sargassum seaweed. The dust contains iron, nitrogen and phosphorous that fertilizes plankton and seaweed blooms. These thick atmospheric dust plumes corresponded with a sargassum spike in 2015 and the worst incursion of sargassum in 2018.^v

What, then of the fundamental claim of sea-level rise?

A realistic expectation of sea level rise in the Mexican Caribbean

That’s the promising title to a study^vi that appeared in December 2019 in the Journal of Ocean Engineering and Science.

The Guardian article warned that “[r]ises in sea level driven by the climate crisis could reach 40cm (15in) by 2050”. And scientific study claiming to assess a realistic expectation of sea level rise?

Sea level rise by thermal expansion is likely less than 0.7 mm/yr.

Subsidence is main contributor of sea level rise in many areas of the world.

The sea level rise is assessed for Cancun and Playa del Carmen.

The likely relative sea level rise is 67–76 mm higher by 2050.

A bit of a difference, I would say, especially as subsidence, rather than actually rising sea levels, is postulated a main contributor:

While there is no information about the relative rate of rise of the sea level (and the acceleration) in Cancun, two GPS domes are located between Cancun and Playa del Carmen. The GPS dome of CNC0 shows over the time window 2007.42 to 2018.84 a subsidence of −2.463 ± 0.806 mm/yr. while the GPS dome TGMX shows over the time window 2015.14 to 2019.02 a subsidence of −2.733 ± 2.231 mm/yr. Hence, the area of Cancun is very likely subjected to subsidence…

We are also told:

There are very few tide gauges in Mexico along the shores of the Gulf, and none of them satisfies minimal length and quality requirements to compute trends. The tide gauge closer to Cancun in Puerto Morelos, in between Cancun and Playa del Carmen, of poor-quality data and time span only 2007 to 2013. Possibly the best tide gauge around Cancun is Progreso, of a time span of data 1952 to 2013 but completeness only 54%, with data basically collected up to 1984 and then only a few, latest measurements, that however, it does not permit to compute any trend.

The Progreso Tide Guage Data is available^vii, but as the study says, it is incomplete. Insofar as any trends can be discerned, however, they certainly do not include accelerating sea level rise, and in the absence of sea level rise acceleration, then it isn’t a function of climate change.

GOM20: A Stable Geodetic Reference Frame for Subsidence, Faulting, and Sea-Level Rise Studies along the Coast of the Gulf of Mexico

This is the rather comprehensive title to another study^viii which seeks to draw together the evidence around sea level rise and land faulting and subsidence around the Gulf of Mexico. It was published on 21^st January 2020, so is also a relatively recent contribution to our knowledge of this subject.

Coastal sea-level is often monitored by tide gauges. Tide gauge measurements are relative to nearby benchmarks fixed on land, which is historically surveyed by periodic leveling surveys and recently by Global Navigation Satellite System (GNSS) surveys. To be reproducible and comparable within a large area and over a long-time span, the benchmark and sea-level measurements must be evaluated in a well-defined and consistent frame of reference. However, the research community has difficulties in establishing a unified and consistent datum (reference frame) across the entire GOM region to evaluate long-term land deformation and sea-level changes. Different reference systems (or simply reference points) have been utilized in different areas during different periods by different researchers. Thus, it is a challenge to incorporate the published ground deformation and sea-level change results into a regional reference system. There is considerable disagreement over the rates and spatial and temporal variations of subsidence along the GOM coast, which eventually leads to controversies over the long-term impacts of coastal subsidence and sea-level rise.

CNC0 is a COCONET station located in Cancun, Mexico. CNC0 recorded steady subsidence of 1.4 mm/year (2007–2019). Another GNSS station (UNPM), located in Puerto Morelos, 35 km south of Cancun, Mexico, also recorded steady subsidence of 1.4 mm/year. Three selected GNSS stations (TAMI: 2009–2019, VIL2: 2003–2019, and PROX: 2011–2015) for estimating the vertical land movement at four tide gauge sites along the Mexico coast also recorded subsidence rates of approximately 1.5 mm/year (with respect to GOM20). There is no considerable vertical crust deformation within the southern GOM region and there is no massive groundwater and oil gas extractions along the southern coast of GOM. Thus, the vertical ground movement trends derived from these four GNSS stations provide reliable estimates of the long-term vertical land movements at their corresponding tide gauge sites.

The study makes clear the difficulties involved in assessments of this type, but also, I think, provides fairly clear confirmation that the land in the area in question is subsiding at the rate of 1.4 – 1.5 mm p.a. And that’s nothing to do with climate change.

That leaves one last major claim – increasing, climate change driven, tropical cyclone activity in the region. Is the claim made out?

Climate Change Indicators: Tropical Cyclone Activity

The United States Environmental Protection Agency offers us an indicator which “examines the frequency, intensity, and duration of hurricanes and other tropical storms in the Atlantic Ocean, Caribbean, and Gulf of Mexico.”^ix

That would seem to be a good place to seek confirmation or otherwise of the claim. Helpfully, it treats us to some key bullet points:

Since 1878, about six to seven hurricanes have formed in the North Atlantic every year. Roughly two per year make landfall in the United States. The total number of hurricanes (particularly after being adjusted for improvements in observation methods) and the number reaching the United States do not indicate a clear overall trend since 1878

According to the total annual ACE Index, cyclone intensity has risen noticeably over the past 20 years, and eight of the 10 most active years since 1950 have occurred since the mid-1990s… Relatively high levels of cyclone activity were also seen during the 1950s and 1960s.

The PDI… shows fluctuating cyclone intensity for most of the mid- to late 20^th century, followed by a noticeable increase since 1995 (similar to the ACE Index). These trends are shown with associated variations in sea surface temperature in the tropical North Atlantic for comparison…

Despite the apparent increases in tropical cyclone activity in recent years…changes in observation methods over time make it difficult to know whether tropical storm activity has actually shown an increase over time.

That is most certainly not a clear endorsement of any claim that hurricane activity in the area is increasing. In fairness to the Guardian, it does not make that claim. It hints at it by referring to damage caused by Hurrican Wilma and Hurrican Dean and claiming that 2020 was “one of the most active hurricane seasons on record”. It’s only actual claim in this regard is that “[h]urricanes are expected to increase in intensity due to higher ocean temperatures, leading to storm surges and exacerbating beach erosion.”

That’s not the same as a climate crisis hitting home, which is what the Guardian’s headline claims. And it’s speculation, pure and simple, which can’t be proved one way or the other until after the event.

Conclusion

The claims of a climate crisis in the Cancun area are not made out. Interestingly, although not – of course – reflected in the headline, the Guardian does admit that there are other factors at work:

This development [rapid population growth and associated infrastructure] is worsening the region’s problems, Escalante says: “I think the way hotels are built has probably contributed more to the loss of the beaches than sea level rise.” Resorts have been built on the dunes, cutting the process of beach formation in a phenomenon known as coastal squeeze.

The Guardian article is written from the viewpoint of local hotel owner, José Escalante, who is selling the six hotels he co-owns, because of his fears for the future (which, by the way, as well as including climate change and seaweed, also include “the large chains with few local connections opening restaurants and beach bars, and organised crime, which makes security a worry.” So, it’s far from being just about climate change, and his decision to sell presupposes that he can find willing buyers – other businessmen who don’t share his concerns – about climate change or otherwise.

Furthermore:

At least 91 big tourist projects are under construction in the state, according to the Mexican environmental watchdog Bios Política.

In other words, a lot of other businessmen don’t think that the sun is setting on Mexico’s paradise beaches as the “climate crisis hits home”. The claim is bunkum.

Endnotes

i https://cliscep.com/2021/11/28/the-gambia-gambit/

ii https://cliscep.com/2022/02/01/volte-face/

iii https://www.theguardian.com/environment/2022/mar/14/mexico-cancun-beaches-tourism-sea-levels-climate-crisis-quintana-roo

iv https://www.bbc.co.uk/news/science-environment-48869100

v https://phys.org/news/2021-08-huge-blooms-brown-seaweed-piling.html

vi https://www.sciencedirect.com/science/article/pii/S2468013319300567

viihttps://psmsl.org/data/obtaining/stations/690.php

viii https://www.mdpi.com/2072-4292/12/3/350/html

ix https://www.epa.gov/climate-indicators/climate-change-indicators-tropical-cyclone-activity