Source: MakeLemonade.nz
Geneva – Climate change is widespread, rapid, and intensifying, and some trends are now irreversible, the UN’s Intergovernmental Panel on Climate Change (IPCC) report says.
Human-induced climate change is already affecting many weather and climate extremes in every region across the globe. Aotearoa is heading into winter and who knows if or how man people will die from flooding or heavy storms this year?
Scientists are also observing changes across the whole of the planet’s climate system; in the atmosphere, in the oceans, ice flows, and on land.
Many of these changes are unprecedented, and some of the shifts are in motion now, while some, such as continued sea level rise, are already irreversible for centuries to millennia ahead.
But there is still time to limit climate change, IPCC experts say. Strong and sustained reductions in emissions of carbon dioxide (CO2) and other greenhouse gases, could quickly make air quality better, and in 20 to 30 years global temperatures could stabilize.
The internationally-agreed threshold of 1.5 degrees above pre-industrial levels of global heating is perilously close.
The planet is at imminent risk of hitting 1.5 degrees in the near term. The only way to prevent exceeding the threshold, is by urgently stepping up our efforts, and persuing the most ambitious path.
In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years, and concentrations of methane and nitrous oxide were higher than at any time in the last 800,000 years.
Global surface temperature has increased faster since 1970 than in any other 50-year period over a least the last 2,000 years. For example, temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6,500 years ago, the report indicates.
Meanwhile, global mean sea level has risen faster since 1900, than over any preceding century in at least the last 3,000 years.
The UN scientists on the IPCC say human activities affect all major climate system components, with some responding over decades and others over centuries.
Scientists also point out that evidence of observed changes in extremes such as heatwaves, heavy precipitation, droughts, and tropical cyclones, and their attribution to human influence, has strengthened.
They add that many changes in the climate system become larger in direct relation to increasing global warming.
This includes increases in the frequency and intensity of heat extremes, marine heatwaves, and heavy precipitation; agricultural and ecological droughts in some regions; the proportion of intense tropical cyclones; as well as reductions in Arctic sea ice, snow cover and permafrost.
Changes to the ocean, including warming, more frequent marine heatwaves, ocean acidification, and reduced oxygen levels, affect both ocean ecosystems and the people that rely on them, and they will continue throughout at least the rest of this century.
Experts warn that for cities, some aspects of climate change may be magnified, including heat, flooding from heavy rain and sea level rise in coastal cities.
The UN’s secretary general António Guterres has asked New Zealand’s Dr Rod Carr to join an elite world group to look into climate change issues. Dr Carr is chair of the He Pou a Rangi New Zealand Climate Change Commission.
Guterres launched his expert world group to develop stronger and clearer standards for net-zero emissions pledges including businesses, investors, cities and regions and to speed up their implementation.
