GWR 2022 Selection - Flipbook - Page 1
Almost all scientists
now agree that human
activity is causing
global warming, which
is driving increasingly
decades have seen
allied to melting ice in
polar regions. Rising
sea levels have led
to stronger storm
surges, while hotter,
drier summers have
resulted in more
savage wildfires. If left
unchecked, both the
human and ecological
cost of these
trends could prove
Warmest average global
ocean surface temperature
In 2019, the heat content for the upper
2,000 m (6,560 ft) of the world’s oceans
rose above the 1981–2010 average by
228 zettajoules – or 228 billion trillion
Joules. This equates to a temperature rise
of 0.075°C (0.135°F). That may sound like
a tiny increase, but its effects on marine
ecosystems are already taking their toll,
particularly in coastal waters (see p.42).
Highest temperature on Earth
On 10 Jul 1913, a reading of 56.7°C (134°F)
was registered at Greenland Ranch in Death
Valley, California, USA. There is some debate
about the accuracy of such old data, though.
On 16 Aug 2020, a temperature of 54.4°C
(129.9°F) was reliably registered at
Furnace Creek in Death Valley.
Heat extremes in 2020 were not limited
to Death Valley. The greatest temperature
range at one location is 105°C (188°F) in
the Russian town of Verkhoyansk, spanning
from a low of -68°C (-90°F) in 1892 to a
high of 37°C (98°F) in 1982. On 20 Jun
2020, this range may have extended as
Verkhoyansk reportedly hit 38°C (100.4°F).
This would also beat the highest Arctic
temperature (see below). Both 2020
readings are still awaiting verification by the
World Meteorological Organization (WMO).
Highest dewpoint temperature
The “dewpoint” marks the temperature
to which air must be cooled to become
saturated with water vapour, and is one
method of determining humidity. At 3 p.m.
on 8 Jul 2003, Dhahran in Saudi Arabia
logged a dewpoint of 35°C (95°F) with an air
temperature of 42°C (108°F). This resulted
in an apparent temperature (i.e., “what it
feels like”) of 81.1°C (178°F).
Highest “low” temperature in one day
Across a 24-hr period on 26 Jun 2018,
the air temperature in the Omani coastal
city of Quriyat did not drop below 42.6°C
(108.7°F). The previous highest low was
41.7°C (107.1°F), recorded at Khasab
Airport – also in Oman – on 27 Jun 2011,
and equalled in Death Valley on 7 Jul 2012.
First use of the term “climigration”
Human settlements have always been at the
mercy of changing environmental factors, but
the recognition that we could be partly driving
these changes only really gained traction in the late
20th century. In 2009, lawyer Robin Bronen (USA)
coined the term “climigration” to describe the forced
movement of people as a result of climate change.
She included it in a report on indigenous Alaskan
villages (such as Shishmaref, above), whose
residents had to relocate owing to vanishing
sea‑ice and thawing permafrost.
Polar be on
seals, b ving their
sea-ice her afield,
Highest sea-level rise
The year 2019 marked the
greatest rise in sea levels since
satellite altimetry observations
began in 1993. The global average
was 87.61 mm (3.4 in) above
that of 1993, according to the
National Oceanic and Atmospheric
Administration (NOAA) – an
increase of 6.1 mm (0.24 in) from
2018. Kiribati (pictured) is a lowlying atoll in the Pacific particularly
at risk; rising oceans may
soon force its 100,000-plus
population to relocate.
Greatest ice-sheet melt in one day
Observations and modelling indicated that,
on 31 Jul 2019, the Greenland Ice Sheet (GIS)
generated 24 billion tonnes (26.5 billion tons)
of meltwater in 24 hr – enough to fill 10 million
Olympic-sized swimming pools. Some of this
refroze on to the ice sheet, but more than half
– 15.3 billion tonnes (16.9 billion tons) – is
thought to have run into the ocean.
As the GIS is the world’s
second-largest body of ice
(after the Antarctic Ice
Sheet), this has severe
ramifications for global
sea levels (see above).
Largest dead zone
The Gulf of Oman – a
stretch of sea between Oman and
Iran – contains the largest oxygen
minimum zone (OMZ, aka a “dead
zone”). Oxygen concentrations
often drop below 6 micromoles
(µmol) per kg across the area, far
under the 120 µmol/kg required to
sustain many forms of life. There
has always been an OMZ here, but
since the 1990s it has grown and
intensified, owing to warming seas.
This has led to a huge decline in
biodiversity, allowing vast algal
blooms (above) to form.
According to NOAA’s National Ice Center,
which monitors major icebergs using
live satellite data, iceberg A23A was
40 nautical mi long and 34 nautical mi wide
(74 x 63 km; 46 x 39 mi) as of 8 Jan 2021.
Located in the Weddell Sea off Antarctica,
it had an area of c. 4,000 km2 (1,540 sq mi)
– similar to the US state of Rhode Island.
The previous record holder – A68A – broke
into several fragments as it neared the
island of South Georgia in late 2020.
Largest ozone hole
The ozone layer is a thin section of Earth’s
atmosphere that absorbs most of the Sun’s
harmful UV radiation. Certain air pollutants
deplete ozone molecules, causing thinning
or even gaps in this natural shield. On 9 Sep
2000, a 29.9-million-km² (11.5-millionsq‑mi) hole – about three times the size
of the USA – appeared above Antarctica.
Despite shrinking to less than half that size
in Oct 2019, the following year it had grown
back to 24.8 million km2 (9.6 million sq mi).
Lowest Arctic sea-ice extent
Each winter, the Arctic Ocean freezes and forms
sea-ice that shrinks the following summer. Only
3.41 million km2 (1.31 million sq mi) of ice remained
at the end of the Arctic summer in 2012, as recorded
on 16 Sep. The next-lowest levels – 3.74 million km2
(1.44 million sq mi) – were seen in 2020, when it’s likely
the Arctic experienced its highest-ever temperatures
(pending WMO ratification). The inset NASA heat
map shows 2020’s uncommonly hot spring season,
particularly in northern Russia and Alaska, USA.
Most named tropical
storms in one year
Storm events are grouped into
categories based on their wind
speed; they receive a name once
they reach the status of “tropical
storm”, with sustained winds of
33 knots (61 km/h; 38 mph) or
higher. The all-time record goes to
1964, when 38 named cyclones
were logged in the West Pacific; of
these, 26 escalated into typhoons.
The Atlantic witnessed its most
intense storm season ever in 2020.
In total, there were 30 named
storms, 13 of which became
hurricanes (as typhoons are called
in the northern hemisphere). The
season ended with Hurricane Iota
(pictured is the Colombian isle of
Providencia, post-Iota). It is only
the second-known Category 5
hurricane to occur in November;
the first was back in 1932.
Largest injection of smoke into
the stratosphere by a wildfire event
Between Dec 2019 and Jan 2020, fierce
bushfires burned some 5.8 million ha
(14.3 million acres) of Australia – an area
larger than Croatia. They also spawned a
series of huge pyrocumulonimbus clouds.
Around 400,000 tonnes (440,000 tons)
of aerosol particles (a mix of carbon,
smoke and condensed water) –
similar in quantity to that produced
by a moderate volcanic eruption
– rose some 35 km (22 mi) into
the sky. Millions of animals
perished and air quality
as far away as South
America was affected.
Global warming makes
bushfires more frequent
and more intense: less rainfall
results in drier forest and grassland, far
more susceptible to catching alight.
Largest climate-change protest
The Global Climate Strike in Sep 2019 was a
week-long mobilization calling for more action on
the climate crisis. It was spearheaded by Fridays For
Future and School Strike 4 Climate – championed by
Greta Thunberg – working with grass-roots activists,
NGOs and charities. Across the two main strikes (20 Sep
and 27 Sep), an estimated 7.22 million people in more
than 160 countries took part (above is London, UK, on
20 Sep). There was even a rally in Antarctica, the
most southerly climate protest (see p.28).
Scorched Earth: 2020’s fire outbreak
Australia was not the only place to see
unprecedented wildfires in 2020. Drier
and hotter climates are turning ever
more terrain into a tinderbox.
• California, USA (below): 1.77 million
ha (4.37 million acres) razed
• Brazil: c. 25% of the Pantanal (largest
wetland) burned, along with nearly
2.2 million ha (5.4 million acres) of the
Amazon (largest rainforest)
• Siberia, Russia: fires emitted around
250 megatonnes (275 million tons) of CO2