📈 Chartpack: The global heatwave
How hot has this summer been, and how has it felt in cities?
Midway upon the journey of our life
I found myself within a forest dark,
For the straightforward pathway had been lost.
[Dante Alighieri, The Divine Comedy, Inferno, Canto 1]
Hi,
here. I was born at 363.48 ppm.1 My mother was born at 320.23 ppm. My grandmother was born at 310.6 ppm. Today, we are at 416.43 ppm. That’s very close to the 450 ppm of carbon dioxide in the atmosphere that will push global warming to 2°C above pre-industrial levels. But what do these abstract numbers actually mean? How do they feel?The global heatwave this summer underscores the harsh reality of accelerating climate change, so we decided to dedicate this week’s Chartpack to it. We’ll look at exactly how hot this summer has been so far, and how the scorching heat has been felt by people around the world.
We have written previously extensively about the techno-economics of climate mitigation. To dig deeper, read the following:
The global issue
Fahrenheit 2023
July 2023 has been a month of relentless record-breaking. After the hottest day and week, we are now experiencing the hottest month globally in 120,000 years.2 According to the Climate Change Institute at the University of Maine, every day since July 3rd has broken the modern-day record high of 16.924°C (62.46°F), which was set on July 24, 2022. The chart below is a striking representation of how incredibly hot it has been this summer.
Riders on the storm
This chart chronicles the number of reported global natural disaster events from 1923 to 2023, including those from extreme temperatures, droughts, wildfires, extreme weather, and floods. We're seeing an undeniable increase in reported natural disasters overall. While it's often difficult to attribute a single event directly to climate change, the upward trend in occurrences is evident.
A warning from the poles
Sea ice is shrinking, fast. In this chart, you can see that the amount of Arctic sea ice is currently the 12th lowest on record, and Antarctic ice extent is a record low. The reality is that we’re entering uncharted waters. Melting ice contributes to rising sea levels, threatening coastal communities, and disrupts weather patterns, leading to more extreme weather events. The loss of reflective ice accelerates global warming, creating a feedback loop that could lead to even more rapid climatic changes. Meanwhile, the ecosystems that depend on these icy habitats, including human communities, face uncertain futures.
Global issue, but locally felt
Hot in the city
The global increase in temperatures is felt with particular intensity in big cities, where extreme heat waves are becoming much more common than only 70 years ago. Phoenix now deals with four times as many searing heat days as in the 1950s, Paris eight times as many, and London ten times as many.
These temperature increases are all the more extreme because of the urban heat island effect, where cities become hotter than the surrounding rural areas due to the concentration of human activities, buildings and roads. The concrete and asphalt absorb more heat, only to release it at night, keeping cities warmer around the clock.
The US hot spots
Roughly a third of Americans are now feeling the swelter, living in areas where the government has issued warnings about extreme heat in the past week. These scorching hot cities, found mainly in the Sunbelt or the southern part of the country, range from Los Angeles to Miami.
Phoenix rising
Arizona is disproportionately touched by these heatwaves, and has seen a record 257 deaths due to the heat in 2022.
As greenery provides an efficient way to help residents cool down, Phoenix, Arizona has a “Tree and shade masterplan”. The idea is to build cool corridors and double the amount of trees by 2030. You can even donate a tree.
The data presented here, from record-breaking temperatures and natural disasters to melting polar ice and intensified urban heat island effects, paints a picture of a world grappling with an immediate and increasingly urgent crisis. For all of us, whatever our ppm at birth, today’s pervasive heat makes those abstract CO2-level numbers all too tangible.
Ppm stands for "parts per million", referring to the number of carbon dioxide molecules per million molecules of dry air.
Based on paleoclimatology.
For more on trees you can see how tree cover effected urban temperatures in UK during heatwave last year https://news.sky.com/story/heatmaps-reveal-the-warmest-and-coolest-areas-of-five-english-cities-and-the-impact-of-green-spaces-12923232