‘Climate collapse’ warning as air quality drops during heatwaves: UN chief

The news came when the UN chief released a strongly worded statement in a record summer of global warming in the Northern Hemisphere, according to The European Union’s climate service Copernicus and WMO.

Earth has just experienced its hottest August ever – by a large margin – and the second hottest month ever after this July. Included in June, they represent the warmest three-month period on record, the data show.

Overall, the year is the second warmest ever after 2016.

The dog days bite back

“Our planet has just endured a season of simmering – the hottest summer on record,” the UN said Secretary General António Guterreswarns of “climate collapse has begun”.

“The dog days of summer don’t just bark, they bite,” the UN chief continued, describing the consequences of humanity’s unleashed dependence on fossil fuels.

As the climate crisis provokes more and more extreme weather worldwide, the UN Secretary-General urged leaders to “turn up the heat now for climate solutions.”

Heat wave factor

That 2023 WMO Air Quality and Climate Bulletin – comes on the heels of the Secretary-General’s statement – puts a sharp focus on the damage caused by heat waves.

It notes that high temperatures are not only a danger in themselves, but they also trigger harmful pollution.

Based on data from 2022, the report shows how heat waves triggered a dangerous drop in air quality last year.

“Heat waves worsen air quality with knock-on effects on human health, ecosystems, agriculture and indeed our daily lives,” said WMO Secretary-General Prof. Petteri Taalas, who commented on the report’s findings and added that climate change and air quality must be tackled together to break a vicious circle.

Climate change brew

Climate change is increasing the frequency and intensity of heat waves.

“Smoke from forest fires contains a witch’s brew of chemicals that not only affect air quality and health, but also damage plants, ecosystems and crops – and lead to more carbon emissions and thus more greenhouse gases in the atmosphere,” explained Lorenzo Labrador, a WMO. scientific associate of the Global Atmosphere Watch network, which compiled the Bulletin.

Last summer’s northern heat wave led to increased concentrations of pollutants such as particulate matter and reactive gases such as nitrogen oxides.

In Europe, hundreds of air quality monitoring sites recorded levels exceeding the World Health Organization (WHO) guideline ozone air quality levels of 100 μg m–3 over an eight hour exposure.

Urban heating islands need trees

When it comes to heat, city dwellers usually experience the most intense conditions.

With dense infrastructure and numerous tall buildings, urban areas end up with temperatures that are much higher compared to the rural environment.

This effect is usually referred to as creating an “urban heat island”. The size of the temperature difference varies, but can reach up to 9°C at night.

As a result, people living and working in cities experience dangerous heat stress even at night.

However, there is a solution. A study in São Paulo, Brazil found that both temperature and CO2 measurements are partially mitigated by incorporating more green spaces in cities, pointing to the benefits of nature-based solutions to climate change.

The WMO released its report on the eve of International day for clean air for blue skies marked on September 7. The theme this year is Together for Clean Air, focusing on the need for strong partnerships, increased investment and shared responsibility to overcome air pollution.

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