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8 HEALTH AND LABORATORY MAGAZINE

CORAL REEFS WILL

DISAPPEAR IN 10 YEARS

Coral reefs have long been regarded
as one of the earliest and most

significant ecological casualties of
global warming.

In new research pub- differences between coral a long time and can be meant corals had enough intolerable heat stress
lished in the journal PLOS reefs one kilometer apart, hampered by pollution and time to recover in between regularly. Most reefs have
Climate, the future of these our team found that at overfishing. Some species bleaching events. already experienced at
tropical ecosystems – 1.5°C of warming, which grow faster and are more least one such event this
thought to harbor more the world is predicted to capable of recovering With 1.5°C of global warm- decade.
species than any other – reach in the early 2030s quicker. ing above pre-industrial
situation is probably worse without drastic action levels, only 0.2 percent Not all regions are stressed
than anticipated. to limit greenhouse gas Scientists hope that local of these refugia remain. at the same time as heat-
conditions on some reef
waves are not global, nor
At 2°C of warming, safe
emissions, 99 percent of
Climate change is caus- the world’s reefs will expe- tracts will ensure suitable havens from heat for coral do all corals bleach. Some
ing more frequent marine rience heatwaves that are temperatures for corals reefs will no longer exist. coral species are more
heatwaves worldwide. too frequent for them to in the future, even when Preliminary findings from capable of coping with ex-
Corals have adapted to recover. surrounding areas warm. another study (yet to treme temperatures than
live in a specific tempera- These conditions may be others due to their growth
ture range, so when ocean That would spell catastro- possible due to upwelling, complete the peer-review form or the type of algae
temperatures are too hot phe for the thousands of where cooler water is process) would seem to within their tissue.
for a prolonged period, species that depend on brought to the surface, confirm the catastrophic Still, the magnitude and
effects of 1.5°C of global
corals can bleach – losing coral reefs, as well as the or strong ocean cur- warming on coral reefs. frequency of heatwaves
the colorful algae that roughly one billion people rents. Reef managers can
live within their tissue and whose livelihoods and food prioritize these so-called This research was car- predicted in this study
nourish them via photosyn- supply benefits from coral refugia, which offer corals a ried out independently by will probably affect even
thesis – and may eventu- reef biodiversity. greater chance of survival. scientists in the US using a resistant coral species,
different method but the
suggesting the world will
ally die.
THERMAL REFUGIA Finding these refugia is same climate models and lose most of its reef biodi-
Across the tropics, mass difficult, though, as they spatial resolutions. versity. Coral reefs of the
bleaching and die-offs The thermal stress of a are likely to be small and THE FUTURE OF CORAL future are likely to look very
have gone from being rare heatwave can affect corals the resolution of climate REEFS different to the colorful and
over a huge geographic
to a somewhat regular oc- projections that model diverse ecosystems we
currence as the climate has area, like the entire north- changes in ocean temper- Global warming of 1.5°C is know today.
warmed. More frequent ern Great Barrier Reef or atures over time tend to be the lower limit that world
heatwaves mean that the archipelagos like the Mal- too coarse. leaders aspired to maintain Climate change is already
time corals have to recover dives. A marine heatwave Our team increased the when they signed the Paris degrading coral reefs
in 2015-16 caused wide-
globally. Now we know
is getting shorter. agreement in 2015. This
spread bleaching in each resolution of climate model that protecting the last
In a 2018 report, the Inter- of the Pacific, Atlantic, and projections by downscaling target is moving further out remaining temperature
governmental Panel on Indian Oceans. them with historical data of reach. refuges will not work on its
Climate Change predicted Corals are small polyp-like from satellite observations For coral reefs, there is own. Slashing greenhouse
that 1.5°C of global warm- to find out where refugia no safe limit to global gas emissions this decade
ing would cause between animals that form colonies are likely to persist in the warming. Given the rate at is the best hope for saving
70 and 90 percent of the of thousands by secret- future. which the global average what remains.
world’s coral reefs to dis- ing a calcium carbonate We found that, from 1986 temperature is increasing,
skeleton that builds a reef.
appear. marine heatwaves are like-
Corals grow slowly, so their to 2019, 84 percent of the
Now, with models capable recovery following bleach- world’s reefs offered suffi- ly to become so frequent
of examining temperature ing and die-offs can take cient thermal refuge. This that most of the world’s
coral reefs will experience