Are Coral Reefs Doomed Within the Next Few Years?

A recent science news report stated that, according to a study signed by 160 researchers, the destruction of coral reefs is now almost certainly irreversible. The report says that most coral reefs will die once global warming exceeds 1.5 degrees Celsius compared to pre-industrial levels.

At present, the climate has warmed by 1.4 degrees, according to scientists, which means that the temperature leading to the irreversible collapse of reefs is expected to be reached within the next few years. When that happens, for example, the ice sheets of Greenland and West Antarctica are likely to collapse.

And that’s not all — according to the lead author of the report, Tim Lenton, one of the tipping points involves the collapse of existing ocean currents, which would have catastrophic consequences. If this were to occur in the ocean circulation system known as the Atlantic Meridional Overturning Circulation (AMOC), it would disrupt the global climate and, among other effects, cool the winters of Finland and the rest of Europe.

* * *

I wanted to highlight this topic because the report provides a clear prediction — one that will be fascinating, if admittedly frightening, to follow in the coming years. It’s especially intriguing because the timeframe mentioned is “in the next few years,” which to my ears sounds more like less than ten years rather than more. At the very least, it doesn’t imply waiting several decades, as shown by the chart published a couple of years ago by the University of Berkeley, which I’ve copied below.

So, I’ll try to remember to follow this issue in the coming years — and to report on it here in this blog, unless I become too senile before the coral reef catastrophe actually happens.

* * *

Before that, however, it’s worth recalling a study from last year which found that coral reef restoration can accelerate the recovery of coral cover and carbonate production so rapidly that the reefs’ net carbonate budgets resemble those of healthy reefs within just four years. And this occurs under the current climate, which is already 1.4 degrees warmer than in pre-industrial times.

And that’s not all — this year another study was published showing that there are also coral reefs that are recovering. At least some can be found in the Chagos Archipelago, where coral cover on both the fore-reef and the lagoon increased by 59–67% after several years of bleaching.

It remains to be seen, however, whether this change of direction is only temporary — or whether it will prove to be permanent.

Previous thoughts on the same topic:
Climate Warning Signs Were There 130 Years Ago – If Only We Had Noticed
Diverging Findings in Antarctic Ice Sheet Research
Big Deal in the Cold North: Finland vs. Canada

The original blogpost in Finnish:
Tuhoutuvatko koralliriutat lähivuosina?

Exceptionally Warm July Falls Short of Records

This past July was the third warmest on record globally. According to the Copernicus Climate Service, the global average temperature in July was 16.68 degrees Celsius. That is 0.45 degrees higher than the July average for the years 1991–2020, and 1.25 degrees higher than during the pre-industrial period.

In Europe, July was the fourth warmest on record, with an average temperature of 21.12 degrees—1.3 degrees above the reference period.

In Finland, however, no temperature records were approached, as for example, Helsinki’s warmest July on record still remains clearly in 2010, with a 1.2-degree margin. In Northern Finland, Sodankylä experienced its warmest July in 2018.

Finland, however, saw the second longest heatwave in recorded history, with temperatures exceeding 25 degrees Celsius for 26 consecutive days at several weather stations. However, the record remains unbroken: in 2021, a station in Southeastern Finland recorded a heatwave lasting 31 days.

According to these statistics, the average July area of Arctic sea ice was also relatively small—the sixth smallest since records began in 1979. This fits the broader pattern observed since around 2007, where the area of Arctic sea ice collapsed and has since settled into a new, lower range of variability.

Previous thoughts on the same topic:
The Northern Sea Ice Area in 2024 Was Not the Smallest on Record
Northern Sea Ice Area Has Not Responded to Exceptionally High Temperatures
Reevaluating Arctic Sea Ice Melt: A Closer Look at Trends and Predictions

Heat wave in Europe contrasts with the coldness of the Arctic sea

Exceptional temperatures have been reported during this year in many locations. During last weeks the focus has been in Europe, where exceptional temperatures were observed especially in southern part of the continent (example).  

The common theme in those news has been that the exceptional heat would have been due to the global change caused by human actions. I am not denying that, but would like to remind that previously any cold weathers have been neglected by climate scientists as climatic change is a global phenomenon and therefore local cold weathers cannot be used as evidence against global change. Therefore, it would be logical, if the same treatment would be given to warm spells. 

However, climatic science has often pointed out that the change is especially speedy in the Arctic region - actually three times as fast as the global average. Therefore I have been following the area and extent of the Arctic sea ice reported by National Snow & Ice Data Center (NSIDC).

Interestingly indeed, the extent of the Arctic ice is right now more wide than in any of the last 13 years at the same date (July 23). That is in accordance with my analyses of correlation between the area of the Arctic sea ice and atmospheric carbon dioxide content: there has been no statistically significant change between them since year 2002 (the link above is in Finnish, but here is an earlier blogpost in English).

Taken together, based on the local temperatures no clear picture on the global warming can be given. However, we may question the extra rapid warming of the Arctic region - and therefore also climatic models predicting that.

Previous thoughts on the same topic:
G-index challenges the theory of the global climatic change
Measurements of arctic temperatures and sea ice area agree with each other
Arctic ice sheet does not support greenhouse gases as the cause of accelerating global warming

 

Measurements of arctic temperatures and sea ice area agree with each other

Antti Lipponen of the Finnish Meteorological Institute tweeted on the arctic temperature, which - according to him - was 4.9℃ warmer than the March average between 1951-1980. He also told that it was fourth highest since March 1950, and showed the following figure.

That accords relatively well with the area of the arctic sea ice  (which should be small when the temperature has been high) in March between years 1987-2022, but differs in its early part of the data, although the area of the ice is sixth smallest since 1987. This NSIDC-data based figure is presented below.

 

I do not criticize the data presented by Lipponen or NSIDC, but want to point out that the trend line of both arctic temperature and arctic sea ice - based only on the latest years - could also be interpreted differently. Namely, the trend line based on more than a decade of the data presented by Lipponen and on nine last years of the sea ice data would point towards recent arctic cooling instead of continuous warming. 

Based on this we should ask, whether the current climate models unanimously forecasting continuous warming in the northernmost parts of the planet should be re-evaluated and better fitted to the data? Or at least, to be more cautious with our interpretations as long as the trend visible in the figures above - and similar trends in data sets for other months or whole years - will continue in becoming years. 

Previous thoughts on the same topic:
Arctic ice sheet does not support greenhouse gases as the cause of accelerating global warming