A hot topic over the past couple of weeks has been the heatwave that has been scorching large parts of Europe. This week has been no different with more than 200 monthly temperature records broken across France, and countries including Switzerland, Austria, Germany and Spain recording all-time highs. For example, Cazaux and Bordeaux experienced monthly all-time temperature records of 41.9C and 40.5C respectively.
One consequence of this prolonged heat is the drying out of soil and vegetation, permitting the development of wildfires across Spain, with tens of thousands of acres of land likely to be affected. According to scientists at the University of Lleida in Spain, climate change will extend the duration of fire seasons across many regions of Europe.
Further heat has been experienced across the US this week, stretching from Texas to Dakota, with parts of the central plains recording highs of 40C every day. The heat index (a combination of air temperature and relative humidity) has been closer to an uncomfortable 43C during the hottest part of the day, in the mid-afternoon. Even Chicago to the north had its hottest temperature in 10 years, of 37.2C. To make matters worse, temperatures did not drop massively overnight, with minimum daily temperatures struggling to fall below 30C.
The major impact this week has been on farming, with a predicted 2,000 cattle deaths in Kansas owing to the early season heat. It is believed that heat stress affects the ability of livestock to regulate their body temperatures, thus negatively affecting their behaviour and increasing their susceptibility to disease and heatstroke.
In stark contrast, New Zealand has been experiencing an intense cold snap. Temperatures have already surpassed the nationwide coldest temperature of 2021, with Middlemarch in the Otago region reaching -11.8C on Wednesday. Additionally, Dunedin airport broke its record for the coldest day in June, with -8.6C recorded on Wednesday. For reference, records began in 1972.
This cold spell coincides with the winter solstice (shortest day of the year), with southern parts of New Zealand seeing just eight hours of daylight. Prolonged nights, coupled with clear skies resulting from high pressure, has meant that daytime heat is easily lost, allowing temperatures to rapidly drop far below freezing.