Climate change is undeniably here, as 2023 saw temperature and heat-related records broken in more than half a dozen areas.
Last year was the warmest on record, with the global average near-surface temperature at 1.45 °Celsius above the pre-industrial baseline, according to the World Meteorological Organisation’s (WMO) 2023 State of Global Climate report.
The last decade was also the warmest ten year period on record.
Records were also broken for sea level rise, Antarctic sea ice loss, glacier retreat, and greenhouse gas levels. More than 90 per cent of oceans had experienced a heat wave by the end of 2023.
Extreme melt in both western North America and Europe caused the largest loss of ice since records began in 1950, and the extent of Antarctic sea ice was the lowest on record, smaller by an area equivalent to the size of France and Germany combined than the previous record.
The report identified the rapid uptake of renewable energy sources as a source of hope for climate action, as 510 gigawatts (GW) of new generation was added in 2023.
Furthermore, the report also pointed out that the level of ocean heat waves the world is now experiencing are forecast to continue and create “change which is irreversible on scales of hundreds to thousands of years” through acidification and the destruction of reefs and ecosystems.
Studies are already showing that higher temperatures is forcing marine ecosystems to move, as oxygen reductions drive habitat loss and further compromise marine species’ abilities to survive changing climates.
Less food, more displacement
Those temperature and weather records are now having a measurable impact on food production.
Weather and climate extremes are aggravating factors for the doubling of the number of people who are acutely food insecure worldwide to 333 million, according to the report.
“The climate crisis is THE defining challenge that humanity faces and is closely intertwined with the inequality crisis – as witnessed by growing food insecurity and population displacement, and biodiversity loss” said WMO Secretary-General Celeste Saulo.
More extreme cyclones, surface heatwaves, bushfires, droughts and floods led to the deaths of hundreds and displacement of millions of people globally.
And while global climate-related finance flows doubled year-on-year to almost $US1.3 trillion ($A2 trillion) in 2021/22, they still only represent 1 per cent of global GDP, according to the Climate Policy Initiative.
The WMO report estimates the annual figure needs to $US9 trillion by 2030 and $US10 trillion by 2050 to counter the effects of climate change. It puts the bill, if nothing is done, at $US1,266 trillion.
Adaptation finance was a mere $US63 billion in 2021/2022, well below the estimated $US212 billion per year needed up to 2030 in developing countries alone.
The numbers are wrong
The WMO report paints a grim picture of the state of the world, but some researchers believe the situation is much, much worse.
The day before the WMO report was released, scientists at the University of Vienna published a study indicating an error in the established method of calculating global heat days.
The result is that they suspect a “systematic underestimation in the frequency of heat days” and in future, an overestimation of the rise in heat days.
Set numbers of days, called “moving time windows”, are used to calculate temperatures and measure them against regionally-specific baselines.
What the Vienna scientists found is that many previous studies expanded that window from an originally recommended five days to 31 days. The result is to add seasonal cycles into the mix and inadvertently introduce lower temperatures from different seasons into calculations, and therefore lower the probability of extremes.
“Heat days are often defined as the 10 per cent warmest days at each location. However, we were able to show that an error in the calculation can lead to a considerable underestimation in the number of extreme days. This has been overlooked in many studies so far,” says Lukas Brunner, the lead author of the study and senior scientist at the Department of Meteorology and Geophysics at the University of Vienna.
Regions particularly affected include the western United States and the Arabian Peninsula, where only 7 per cent heat days are detected by the algorithm instead of the correct 10 per cent, leading to a relative error of -30 per cent.
The 31 day window however still allowed for accurate calculations in Europe.
“By the end of the century, in hotspot regions like the Arabian Peninsula, almost every day will be considered a heat day by today’s standards. But due to the error the historical period has only 7 per cent heat days instead of the correct 10 per cent, leading to an overestimation in the increase.”
