Antarctica sea ice has fallen to an “alarming” level during the southern hemisphere summer, scientists have revealed.
The ice surrounding Earth’s southernmost continent now measures less than 772,200 square miles (2 million square kilometers), or about the size of Mexico.
Worryingly, this is the third year in a row that this figure has fallen below this threshold, according to the US National Snow and Ice Data Center (NSIDC).
Less sea ice can threaten the habitats of penguins, seals and other Antarctic animal species, and also contributes to global sea level rise.
Unfortunately, there is also a record low for Antarctic sea ice during the winter.
Antarctica’s “sea ice extent” refers to the ice surrounding the coast of Antarctica. Here, the average sea ice extent between 1981 and 2010 for this time of year is marked in orange, but in much of this area the ice is now “missing”
Sea ice plays an important role in maintaining the Earth’s energy balance while also helping to keep the polar regions cool due to its ability to reflect more sunlight back into space. Pictured is sea ice in the water off Cuverville Island in Antarctica.
Walt Meier, a research scientist at the NSIDC, said experts “still don’t know the full reason” why sea ice is now at a record level, although “global warming certainly could be a factor.”
“It appears that warm ocean temperatures are important, but other factors may be at play, including wind patterns,” he told MailOnline.
‘We only have 45 years of high-quality data, which may not yet reflect all the variability of Antarctic sea ice.
“However, since 2016, Antarctic sea ice has for the most part been much lower than normal, with record lows at times.”
Professor Martin Siegert, a glaciologist at the University of Exeter, agreed that “we don’t know for sure” what the cause is.
“It would be nice to have a definitive answer, but it doesn’t really matter much,” he told MailOnline.
“We certainly can’t afford to attribute it to variability as an excuse for not stopping the burning of fossil fuels; that would be crazy.”
Antarctica’s sea ice is vitally important because it reflects sunlight, which helps keep the polar regions cool.
Without this ice cover, dark areas of the ocean are exposed, absorbing sunlight instead of reflecting it, which in turn warms the region and further accelerates ice loss.
Climate scientists constantly track sea ice extent throughout the seasons and compare its size to the same months in previous years to see how it is changing. Data from the National Snow and Ice Data Center have recently shown that sea ice extent is below average since records began, regardless of the time of year.
According to the NSIDC, the five-day average sea ice cover fell to 768,343 square miles (1.99 million square kilometers) on February 18.
It then fell further to 764,482 square miles (1.98 million square kilometers) on February 21.
This is still not as severe as the record minimum ice extent set in February 2023 of 683,400 (1.77 million square kilometers).
However, if we look at the bigger picture, the three lowest years on record are the last three years, according to scientists.
Ice sheet surface melt on the Antarctic Peninsula slowed sharply in mid-January and remained low until February 15.
Because it is summer in the Southern Hemisphere, most of Antarctica’s ice is currently estimated to be only 3 to 6.5 feet (1 to 2 meters) thick.
Dr. Ariaan Purich, a climate scientist at Monash University in Australia, believes the ice is thinner than usual since it re-formed after the winter.
“It seems plausible, and thinner sea ice could melt more quickly,” Dr. Purich said. the Guardian.
Antarctica’s “sea ice extent” refers to the ice surrounding the coast of Antarctica and does not include ice covering the continental landmass.
Due to colder temperatures, sea ice reaches its maximum extent in the southern hemisphere winter (July to September).
But temperatures gradually rise and reach a minimum during the southern hemisphere summer (December to February).
As in the Arctic, the ocean surface around Antarctica freezes in winter and melts each summer. Antarctic sea ice (pictured) generally reaches its annual maximum extent in mid to late September (winter) and reaches its annual minimum in late February or early March (summer).
Climate scientists constantly track sea ice extent throughout the seasons and compare its size to the same months in previous years to see how it is changing.
So while there is great variability in ice extent depending on time of year, it is lower than the average since records began, regardless of the season.
Last year, during the southern winter, the NSIDC reported that Antarctic sea ice levels are at a “mind-blowing” record low for the time of year, at less than 6.5 million square miles (17 million square kilometers).
This is 580,000 square miles (1.5 million square kilometers) less than the September average and is equivalent to five times the size of the British Isles.
Ice melting in parts of Antarctica, including the Antarctic Peninsula, was also above average between mid-January and mid-February.
In a recent blog post, NSIDC also said that weather conditions from January 15 to February 15 continued to be warm in central West Antarctica, where air temperatures were 4°F (2°C) above average from 1991 to 2020.
Meanwhile, ice on the Antarctic Peninsula – the part of the continent that sticks out like a tail – fell sharply in mid-January and remained low until February 15.
Rapid warming has already caused a significant southward shift and contraction in the distribution of Antarctic krill, a keystone species, activists said.
A recent Greenpeace expedition to Antarctica also confirmed that gentoo penguins are breeding further south as a result of the climate crisis.
Barafu ya bahari ya Antaktika imeshuka hadi kiwango cha "kuogopesha" wakati wa majira ya joto ya kizio cha kusini, wanasayansi wamefunua. Barafu inayozunguka bara la kusini zaidi la Dunia sasa inagusa kilomita za mraba 772,200 (kilomita mbili milioni za mraba), au karibu ukubwa wa Mexico. Hii ni mwaka wa tatu mfululizo kwa takwimu za theluji kuanguka chini ya kiwango hicho, kulingana na Kituo cha Takwimu cha Kitaifa cha Theluji na Barafu cha Marekani (NSIDC). Kupungua kwa barafu ya bahari kunaweza kutishia makazi ya pengwini, sili na spishi nyingine za wanyama wa Antaktika, na pia huchangia kuongezeka kwa kiwango cha bahari ulimwenguni. Kwa kusikitisha, kuna pia kiwango cha chini kabisa cha barafu ya baharini ya Antaktika wakati wa majira ya baridi kali. "Upeo wa barafu ya baharini" ya Antaktika inahusu barafu inayozunguka pwani ya Antaktika. "Hapa, wastani wa barafu ya bahari kati ya 1981 na 2010 kwa wakati huu wa mwaka ni alama ya machungwa, lakini katika sehemu kubwa ya eneo hili barafu sasa ni ""kutoweka"" Barafu ya bahari ina jukumu muhimu katika kudumisha usawa wa nishati ya Dunia wakati pia kusaidia kuweka mikoa ya polar baridi kutokana na uwezo wake wa kutafakari mwanga zaidi wa jua nyuma katika nafasi." Picha hiyo ni barafu ya baharini katika maji ya Kisiwa cha Cuverville huko Antaktika. "Walt Meyer, mwanasayansi wa utafiti katika NSIDC, alisema wataalamu ""bado hawajui sababu kamili"" kwa nini barafu ya bahari sasa iko katika kiwango cha rekodi, ingawa ""kuongezeka kwa joto la dunia kwa hakika kunaweza kuwa sababu.""" "Tuna miaka 45 tu ya data ya ubora wa juu, ambayo inaweza bado haionyeshi mabadiliko yote ya barafu ya bahari ya Antarctic. """ "Lakini, tangu 2016, barafu ya bahari ya Antaktika imekuwa chini sana kuliko kawaida, na mara kwa mara imefikia kiwango cha chini kabisa. "" Profesa Martin Siegert, mtaalamu wa barafu katika Chuo Kikuu cha Exeter, alikubali kwamba ""hatujui kwa uhakika"" ni nini kisababishi." "Ingekuwa vizuri kuwa na jibu la uhakika, lakini kwa kweli haina maana sana", aliambia MailOnline. "Hatuwezi kuweza kuelezea mabadiliko kama kisingizio cha kutokoma kuchoma mafuta ya visukuku; hiyo ingekuwa wazimu. " Barafu ya bahari ya Antaktika ni muhimu sana kwa sababu inaonyesha mwangaza wa jua, ambayo husaidia kuweka mikoa ya polar baridi. Bila kifuniko hiki cha barafu, maeneo ya giza ya bahari hufunuliwa, yakinywea mwanga wa jua badala ya kuubadilisha, ambayo kwa upande wake huongeza joto la eneo hilo na kuharakisha zaidi upotezaji wa barafu. Wanasayansi wa hali ya hewa hufuatilia kwa ukawaida kiwango cha barafu ya bahari katika misimu na kulinganisha ukubwa wake na miezi sawa katika miaka ya awali ili kuona jinsi inabadilika. Takwimu kutoka Kituo cha Kitaifa cha Data cha Theluji na Barafu (NSIDC) zinaonyesha kuwa kiwango cha barafu ya bahari ni chini ya wastani tangu rekodi za theluji zilipoanza, bila kujali wakati wa mwaka. Kulingana na NSIDC, kifuniko cha wastani cha barafu ya bahari kwa siku tano kilipungua hadi kilomita za mraba 768,343 mnamo Februari 18. Kisha ikawa na ukubwa wa kilomita za mraba milioni 1.98 na kufikia ukubwa wa kilomita za mraba milioni 7.642 tarehe 21 Februari. Hii bado si kali kama kiwango cha chini cha kiwango cha barafu kilichowekwa mnamo Februari 2023 cha kilomita za mraba 683,400. Hata hivyo, ikiwa tutaangalia picha kubwa, miaka mitatu ya chini zaidi katika rekodi ni miaka mitatu ya mwisho, kulingana na wanasayansi. Kuyeyuka kwa barafu katika eneo la Antarctica kulipungua kwa kasi mnamo Januari na kuendelea hadi Februari 15. Kwa sababu ni majira ya kiangazi katika Kizio cha Kusini, barafu nyingi za Antaktika zinakadiriwa kuwa na unene wa mita moja hadi mbili tu. "Mtaalamu wa hali ya hewa wa Chuo Kikuu cha Monash, Aryan Purik, anasema: ""Mchanga wa barafu umekuwa mwembamba zaidi kuliko kawaida tangu ulipofanyizwa tena baada ya majira ya baridi kali." "Inaonekana kuwa ya kweli, na barafu nyembamba ya baharini inaweza kuyeyuka haraka zaidi", alisema Dakt. Purich. Mlinzi. "Upeo wa barafu ya bahari" ya Antaktika inahusu barafu inayozunguka pwani ya Antaktika na haijumuishi barafu inayofunika bara la bara. Kwa sababu ya joto la chini, barafu ya bahari hufikia kiwango chake cha juu katika majira ya baridi kali ya kusini mwa dunia (Juli hadi Septemba). Lakini joto huongezeka hatua kwa hatua na kufikia kiwango cha chini wakati wa kiangazi cha kusini mwa dunia (Mwezi wa Desemba hadi Februari). Kama ilivyo katika Aktiki, uso wa bahari karibu na Antaktika huyeyusha wakati wa majira ya baridi kali na kuyeyuka kila majira ya kiangazi. Barafu ya bahari ya Antaktika kwa ujumla hufikia kiwango chake cha juu cha kila mwaka katikati hadi mwishoni mwa Septemba (majira ya baridi kali) na hufikia kiwango chake cha chini cha kila mwaka mwishoni mwa Februari au mwanzoni mwa Machi (kiangazi). Wanasayansi wa hali ya hewa hufuatilia kwa ukawaida kiwango cha barafu ya bahari katika misimu na kulinganisha ukubwa wake na miezi sawa katika miaka ya awali ili kuona jinsi inabadilika. Kwa hiyo, ingawa kuna tofauti kubwa katika ukubwa wa barafu kulingana na wakati wa mwaka, ni chini ya wastani tangu rekodi zilianza, bila kujali msimu. Mwaka jana, wakati wa majira ya baridi kali ya kusini, NSIDC iliripoti kwamba viwango vya barafu ya bahari ya Antaktika viko katika kiwango cha chini kabisa kwa wakati huo wa mwaka, chini ya kilomita milioni 6.5 za mraba. Hii ni kilomita za mraba 580,000 (kilomita za mraba milioni 1.5) chini ya wastani wa Septemba na ni sawa na ukubwa wa Visiwa vya Uingereza mara tano. Kuyeyuka kwa barafu katika sehemu za Antaktika, ikiwa ni pamoja na Peninsula ya Antaktika, pia ilikuwa juu ya wastani kati ya katikati ya Januari na katikati ya Februari. Katika chapisho la hivi karibuni la blogi, NSIDC pia ilisema kuwa hali ya hewa kutoka Januari 15 hadi Februari 15 iliendelea kuwa ya joto katika Antarctica ya Magharibi ya kati, ambapo joto la hewa lilikuwa 4 ° F (C) juu ya wastani kutoka 1991 hadi 2020. Wakati huohuo, barafu katika Peninsula ya Antaktika - sehemu ya bara ambayo inasimama kama mkia - ilipungua sana katikati ya Januari na kubaki chini hadi Februari 15. "Mabadiliko makubwa ya joto yamesababisha mabadiliko makubwa kuelekea kusini na kupungua kwa usambazaji wa krill ya Antaktika, aina ya msingi, ""alisema mwanaharakati." Greenpeace imethibitisha kuwa pengwini wa aina ya Gentoo wanazalisha zaidi kusini mwa Antarctica.