Three penguins on sea ice in the Gerlach inlet next to the Mario Zucchellis station, the Italian base in Terra Nova Bay in the Antarctic. Photo: Liv Cornellisen
Scientists have reacted with frustration to a report by the World Meteorological Organisation saying climate change reached new heights in 2024, with some of the consequences being irreversible over hundreds if not thousands of years.
The organisation's State of the Global Climate Report confirmed that 2024 was likely the first calendar year to be more than 1.5 degrees Celsius above the pre-industrial era, the warmest year in the 175-year observational record.
The report confirms the planet is closer than ever to missing countries' goal of keeping the planet less than 1.5C-2C hotter than before people started burning coal, petrol, diesel and fossil (sometimes called natural) gas.
Each of the past eight years had set a new record for ocean heat, and ice cover was shrinking to new lows on both land and sea, it said.
Photo: AFP PHOTO / NASA / HANDOUT
Scientists are frustrated.
Dr Linden Ashcroft, a lecturer in climate science and science communication at the University of Melbourne, said she'd been providing comments like these for her entire career and wondered if she should try screaming the findings from the tops of buildings or saying them while dancing on TikTok.
Others pointed to the recent drop in Antarctic sea ice as holding particular risks for New Zealand.
In its annual round-up the WMO said record greenhouse gas concentrations combined with El Niño and other factors were combining to drive 2024's record heat.
Atmospheric concentrations of carbon dioxide were now at the highest levels in the last 800,000 years, it said.
The 18 lowest Arctic sea-ice measurements on record were all in the past 18 years, the WMO said, while in Antarctica - where sea ice had previously stayed relatively stable - the three lowest ice extents were all in the past three years.
The largest three-year loss of glacier ice also occurred in the past three years, it said, while the rate of sea level rise had doubled since satellite measurements began.
"While a single year above 1.5C of warming does not indicate that the long-term temperature goals of the Paris Agreement are out of reach, it is a wake-up call that we are increasing the risks to our lives, economies and to the planet," WMO secretary-general Celeste Saulo said in an accompanying statement.
Speaking to the Australian Science Media Centre, Ashcroft called the WMO report the world's most trusted climate report card and said it was frightening to see the climate report looking so dire "yet again".
"However, I'm not sure what researchers can say to this latest update that we haven't said a thousand times before," she said.
"Yes, we have now crossed even more devastating and globally significant thresholds. Yes, these records are breaking because of human-induced climate change. No, there is no other way to explain it. Yes, we can avoid the worst impacts of climate change but we all have to act, and we have to act right now. Yes, we are scared too.
"I've been providing comments like these for my entire career, and honestly, I'm not quite sure what to do next," she said.
"Scream these findings from the tops of buildings? Write my comments in capitals? Saying all this while dancing on TikTok? I don't know. But unless we see real climate leadership from governments and businesses, I will save this response and send it through again next year."
The report estimated long-term global warming was currently between 1.34C and 1.41C compared to the 1850-1900 baseline, noting that a team was examining the differences between different tracking methods with a view to shrinking the range of uncertainty.
It said regardless of the method used, every fraction of a degree of warming mattered and increased risks and costs to society.
Although the WMO said record global temperatures seen in 2023 and 2024 were mainly due to the ongoing rise in greenhouse gas emissions and an El Niño event, other factors may have contributed including changes in the solar cycle, a massive volcanic eruption and a decrease in cooling aerosols.
"Data for 2024 show that our oceans continued to warm, and sea levels continued to rise. The frozen parts of Earth's surface, known as the cryosphere, are melting at an alarming rate: glaciers continue to retreat, and Antarctic sea ice reached its second-lowest extent ever recorded. Meanwhile, extreme weather continues to have devastating consequences around the world," Saulo said.
A man walks in a street covered in mud in a flooded area in Picanya, near Valencia, eastern Spain, on October 30, 2024. Photo: AFP / JOSE JORDAN
Only half of countries had adequate early warning systems for extreme weather and climate events.
The WMO said tropical cyclones, floods, droughts, and other hazards in 2024 led to the highest number of new displacements recorded for the past 16 years, contributed to worsening food crises, and caused massive economic losses.
'Extremely worrying' - Kiwi scientist
New Zealand climate scientist Dr James Renwick, a professor at Victoria University of Wellington, said the report told a now-familiar story of record warming, record ocean heat content, melting ice and accelerating sea level rise, and many extreme weather events globally.
"All extremely worrying, yet apparently of little concern to the world's policy-makers, since there is no sign the world is living up to the Paris Agreement to limit warming to 1.5-2C," he said.
"Greenhouse gas emissions that drive climate change just keep increasing, regardless of the bad news. Perhaps our busy lifestyles and the churn of the 24-hour news cycle means climate change just doesn't have time to register," he said.
"But let's pause for a moment. This latest report is saying global temperatures are higher than they have been for at least 175 years - and yet 2024 will be one of the coldest years this century, as we keep adding warming gases to the atmosphere. Sea level rise is speeding up and will be irreversible for hundreds of years as will glacier ice melt. Reversing ice sheet melt would take thousands of years," Renwick said.
"As sea levels rise, we are changing global coastlines and the map of the world essentially forever. I would hope that information causes policy-makers everywhere to lift their eyes, to take notice and to take action."
Antonia Radlwimmer (left) and Chris Pooley preparing a sea ice core for transport to the University of Otago Physics Antarctic Ice Lab. Photo: Inga Smith
Several scientists picked out the retreat of Antarctic sea ice as a particularly worrying trend for New Zealand, while acknowledging gaps remained in knowledge about how Antarctica's oceans behave.
"For many years, one hold-out in this picture has been Antarctic sea ice extent," Renwick said.
"It kept increasing through the 1990s and 2000s, even though the world was warming. But no longer. The warming of the oceans has finally started to materialise over the surface of the southern oceans and sea ice is paying the price.
"There will be plenty of ups and downs over coming years, but the trend will very likely be down from here."
Dr Alexandra Gossart, a research fellow in regional climate modelling at Victoria University's Antarctic Research Centre, said a warming atmosphere and ocean, along with declining sea ice, was allowing more heat to reach the land-based ice sheet, contributing to ice loss and, ultimately, global sea level rise.
"Although there might have been moments of relative stability in the past, recent years have shown a steady increase in climate records being broken. A young person coming of age today has only ever known a world with rising CO₂ levels, global warming air and oceans, increasing sea levels, shrinking ice sheets and glaciers, and declining sea ice cover," she said.
University of Otago Associate Professor Inga Smith, co-director of the university's Climate Change Research Network said: "Antarctic sea-ice extent had been relatively stable between 1979 and 2016, so the recent changes have alarmed many people.
"The abrupt drops in sea-ice extent at a time when the sea ice should still be growing in winter has been suggested [as what] might be a regime shift.
"The consequences of less sea ice in the Antarctic winter have been reported to include increased storminess in the Southern Ocean, which is already very stormy," Smith said.
"Aotearoa New Zealand is a country directly impacted by what happens in the Southern Ocean and Antarctica, so the sea ice issues and consequences raised in this report should be very concerning to all New Zealanders."
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