95-Degree Days: How Extreme Heat Could Spread Across the World

There is a truly excellent article within the New York Times that clearly lays out the potential impact of the on-going climate change. It is not simply the words, but perhaps the graphics that come with it that help to convey the impact.

95 Degree days

When the temperature soars to 95 F, (35 C) then humans and their food sources are impacted. No only do crops wither, but people are at an increased risk of dying. The NYT article has tapped into a set of interactive graphs created by Climate Impact Lab to effectively communicate this.

By Who?

The Climate Impact Lab

It is basically a collaboration of more than 20 climate scientists, economists, computational experts, researchers, analysts, and students from several institutions. That specifically includes the University of California, Berkeley, the Energy Policy Institute at the University of Chicago (EPIC), Rhodium Group and Rutgers University. It is the University of Chicago (EPIC) that is acting as the hub and so that is where their finance and administration comes from.

There has been a historical disconnect between the data driven conclusions reached by Climate scientists and the public perception of the implications of it all, and so this collaboration is a rather sensible attempt to bridge that gap. They are however specifically aiming to connect to community decision makers.

Climate change is not something that will happen in some far and distant future, it is impacting us now. Record breaking temperatures, the on-going melt in both the Arctic and also the Antarctic, increased costal flooding, rising sea levels, prolonged droughts, intense storms, and more. These are all risks that are increasing.

What Climate Science is revealing is that we need to reduce emissions. To enable communities and policymakers to make informed decisions there is a need for this collaboration between climate scientists and also economists and computational experts to be able to both quantify the impact and have an empirically-derived cost for each and every ton of Carbon Dioxide.

Back to the NYT Article

It articulates what will happen.

Moderate Action: countries would take some measures, but not drastic ones, to curb emissions. This would more or less be the Paris Agreement scenario as it currently stands with no further changes.

The resulting global warming would still cause significant shifts for many cities. In Washington, from 1986 to 2005, an average of seven days each year had temperatures of at least 95 degrees. By the end of the century, the city can expect 29 of these extremely hot days per year, on average. (The likely range is 14 to 46 hot days per year.)

Phoenix is used to the heat, averaging 124 days per year with 95-degree weather. At the end of the century, that’s expected to increase to around 155 days — an extra month of extreme temperatures each year. Madrid would go from eight severely hot days per year to 43, Beijing from nine to 35.

The swings are even greater closer to the equator. New Delhi, India’s capital city, has historically averaged 105 days with temperatures of at least 95 degrees each year. That’s likely to rise to a range of 137 to 200 days per year.

What if we took no action at all?

If the Paris Agreement was abandoned completely, then things would be different …

By 2100, Washington could swelter in 95-degree weather for fully one-fifth of the year — around 74 days, on average. Large swaths of Brazil and sub-Saharan Africa would experience these temperatures for most of the year.

Just to reassure you, this is not the most probable outcome. To some degree, many already get it and steps are being taken all around the planet. Coal use is rapidly declining. The cost of renewables such as solar is shrinking and its use is rapidly increasing.

The Feedback loop

Rather ironically, as the temperatures increase our power consumption also increases (air conditioners), and that in turn causes us to emit even more Carbon Dioxide, unless of course we use renewables to meet that increased demand. Another impact is that crop yields drop, and so to meet the demand we need even more faming activity which in turn … well you get the picture. And speaking of pictures, here is their empirically-derived graph that measures this …

The data source for the above is via: University of California, Berkeley and NBER; Proceedings of the National Academy of Sciences. Via Tamma Carleton/Science


Knowing the projected impact and also the regions that will be impacted enables us to adapt now. A guess is not the best way to make public policy decisions, it really does need to be robust, solid, and also empirically-derived if it is going to be truly effective …

Ultimately, people will be better able to adapt if they have a better idea of what individual cities and regions can expect, said Trevor Houser, who co-directs the Climate Impact Lab. In the United States, some urban planners are already experimenting with techniques like adding green spaces or increasing the reflectivity of rooftops to cool down city centers during heat waves.

“Right now, when you start talking to people about higher temperatures, they tend to think, great, more beach days,” said Solomon Hsiang, a professor of public policy at the University of California, Berkeley who helps direct the lab. “What’s often less appreciated is just how much an extremely hot day can distort our lives in all sorts of ways we don’t often even think about.”

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