It wasn't just Poland that ended the summer with exceptional heat. Both on the scale of the whole Earth and Europe itself, it was record-breakingly hot – even breaking last year's record.
Terribly hot. Extreme weather
Temperature data for June-August was provided by the European climate service Copernicus. In August alone, the global temperature was 0.71 degrees Celsius higher than the average for that month. And the average from 1991-2020 is already higher than the normal climate for us, before the era of global warming. Compared to the pre-industrial period, the August temperature anomaly is as much as 1.51 degrees Celsius.
This difference compared to the average may not seem big, because in the weather we observe a change in temperature sometimes by a dozen or so degrees during the day. However, we are talking about the average for the entire planet, a change of 1.5 degrees in a hundred years means a huge difference.
– Over the past three months, the world has experienced its hottest June and August, its hottest day on record and its hottest summer on record. This series of record temperatures increases the likelihood that 2024 will be a record year as well – said Dr Samantha Burgess, Deputy Director of Copernicus. She emphasised:
The extreme temperature events we witnessed this summer will become more intense, with more devastating consequences for people and the planet, unless we take urgent action to reduce greenhouse gas emissions.
Europe itself also had a record-breakingly hot summer—at least across much of the continent. Parts of the British Isles, Iceland, and Portugal were cooler than usual. Much of the continent had less rain in August than average, fueling droughts and wildfires.
The hottest summer on record
The graph below shows that this year's summer (for the Northern Hemisphere) not only surpassed the record summer of 2023, but also that the temperature anomaly is significantly different from previous years. The temperature was not only higher than the year before, but also significantly different from previous years. There is also a clear trend of progressive global warming. The last 10 years have been hotter than the previous decade, and also significantly above the 90s and 80s.
The latest temperature records continue not only the global warming trend that has been going on for over 100 years, but also the record streak of the last dozen or so months. According to Copernicus, the 12-month period from September last year to August was 1.64 degrees Celsius hotter than the pre-industrial average (1850-1900). Although 2023 was the hottest year on record, 2024 has a very good chance of breaking this record.
Where does this highest temperature range in the history of measurements come from? At the turn of last year and this year, the long-term trend of climate change was superimposed on the natural phenomenon of El Nino, which is the periodic warming of surface waters in the Pacific Ocean. Changes in the Earth's largest ocean have such an impact on the entire planet that El Nino significantly increases the average temperature of the Earth.
Now, the opposite trend is expected, namely La Nina – for at least a few months, the surface of the tropical part of the Pacific will be lower than average. This natural variability can be compared to the seasons – after summer comes winter, and once every few years the Pacific enters the El Nino or La Nina phase. But at the same time, the average temperature of the planet is constantly rising due to our greenhouse gas emissions. When these two effects overlap, we see temperature records. And even if 2025 or 2026 is not a record year, eventually more records will come – and they will come as long as we burn oil, gas and coal and heat the atmosphere.
The hottest in 100 thousand years
The records reported by Copernicus concern the history of measurements, which dates back to around the mid-19th century. Wasn't the Earth hotter, for example, 500 or a thousand years ago? Even if there were no thermometers back then, it doesn't mean that we have no idea about the prevailing temperatures. We can recreate indirectly, by examining trees, coral reefs or glacier cores.
This study will not tell us exactly what the global temperature was in August 5032 BC, but it will show the trend over centuries and millennia.
Thanks to this, we know that global temperature is breaking records not for the last hundreds, but for tens of thousands of years. According to scientists, it is likely that recent years have probably been some of the hottest in the last 100,000 years.
Climate change is driving weather extremes
The increase in average temperature shows us the trend and rate of climate change. However, average temperature alone tells us little about how this change affects our lives. And this impact is becoming increasingly clear as global warming destabilizes the weather, drives extreme phenomena that cause serious losses and can threaten our lives and health.
Climate change fueled deadly summer heat waves in the Mediterranean basin, Mexico and in Asia; it was a key factor drought in Sicilyintensified the typhoon Gaemi and floods in Brazil.
In Poland, apart from heat waves, we saw both record-breaking downpours, including in Warsaw and Zamość (as much rain fell in a day as an average in two months), as well as drought. In the Vistula River at the height of Warsaw, the water level dropped to a record low of 24 centimetres. These two phenomena only seem to exclude each other.
The record downpour in the capital was preceded by hot weeks with almost no rain. And the extremely intense rainfall does very little to improve the water situation. Because such a large amount of water in a short time means that the vast majority of it will run off, and if there is no rain for another week or two, it will become very dry again. This is exactly the scenario that scientists are warning us about in connection with climate change: hot, dry periods interrupted by very heavy rains. Drought and floods can occur right after each other.
How does global warming increase heavy rain? Warmer air holds more water. So the more we heat the planet by emitting gases from burning oil, coal and gas, the more water there will be in the air – and the heavier the rains will be when that water falls. For every degree Celsius of global warming, the atmosphere holds 7 percent more moisture. When that rain falls as rain, it is more intense.