每日英語跟讀 Ep.K414: How climate change drives heatwaves and wildfires in Europe
Europe is in the grip of a record-breaking heatwave and wildfires are raging across the Mediterranean. Here’s how climate change drives these events.
HOTTER, MORE FREQUENT HEATWAVES
Climate change makes heatwaves hotter and more frequent. This is the case for most land regions, and has been confirmed by the UN’s global panel of climate scientists (IPCC).
Greenhouse gas emissions from human activities have heated the planet by about 1.2°C since pre-industrial times. That warmer baseline means higher temperatures can be reached during extreme heat events.
But other conditions affect heatwaves too. In Europe, atmospheric circulation is an important factor.
FINGERPRINTS OF CLIMATE CHANGE
To find out exactly how much climate change affected a specific heatwave, scientists conduct “attribution studies”. Since 2004, more than 400 such studies have been done for extreme weather events, including heat, floods and drought — calculating how much of a role climate change played in each.
This involves simulating the modern climate hundreds of times and comparing it to simulations of a climate without human-caused greenhouse gas emissions.
For example, scientists with World Weather Attribution determined that a record-breaking heatwave in western Europe in June 2019 was 100 times more likely to occur now in France and the Netherlands than if humans had not changed the climate.
HEATWAVES WILL STILL GET WORSE
The global average temperature is around 1.2°C warmer than in pre-industrial times. That is already driving extreme heat events.
Temperatures will only cease rising if humans stop adding greenhouse gases to the atmosphere. Until then, heatwaves are set to worsen. A failure to tackle climate change would see heat extremes escalate even more dangerously.
Countries agreed under the global 2015 Paris Agreement to cut emissions fast enough to limit global warming to 2°C and aim for 1.5°C, to avoid its most dangerous impacts. Current policies would not cut emissions fast enough to meet either goal.
CLIMATE CHANGE DRIVES WILDFIRES
Climate change increases hot and dry conditions that help fires spread faster, burn longer and rage more intensely.
Hotter weather also saps moisture from vegetation, turning it into dry fuel that helps fires to spread.
CLIMATE CHANGE ISN’T THE ONLY FACTOR IN FIRES
Forest management and ignition sources are also important factors. In Europe, more than nine out of 10 fires are ignited by human activities, like arson, disposable barbeques, electricity lines, or littered glass, according to EU data.
Countries, including Spain, face the challenge of shrinking populations in rural areas, as people move to cities, leaving smaller workforces to clear vegetation and avoid “fuel” for forest fires building up.
Some actions can help to limit severe blazes, such as setting controlled fires that mimic the low-intensity fires in natural ecosystem cycles, or introducing gaps within forests to stop blazes rapidly spreading over large areas.
But scientists concur that without steep cuts to the greenhouse gases causing climate change, heatwaves, wildfires, flooding and drought will significantly worsen.
根據二○一五年全球《巴黎協定》，各國同意以足夠快的速度減少排放，以將全球暖化限制在 2°C，並以 1.5°C 為目標，以避免其衝擊達到最危險的地步。目前的政策減少排放的速度不夠快，這兩個目標都無法達到。