Heat islands are urban areas that can have higher temperatures than surrounding rural areas with more greenery.

Heat islands are caused by several factors, including:

the types of materials we use in cities for buildings, pavement, and roads that can absorb more heat than natural surfaces such as leaves or grass

human additions to the sun's heat, such as air conditioning, vehicles, cooking, or machinery

the shapes of our cities that may restrict airflow to carry heat away

the mass of our buildings that can absorb heat and release it gradually, even through the night

More natural, often rural areas with greenery may reflect more light, release moisture and provide shade.

There are ways to help reduce the effect of heat islands, such as planting more urban trees or using green roofs.

Deciduous trees have the handy feature of providing shade for a house in the summer while letting light through in the winter when the leaves fall.

A study using 2015 data found that "doubling tree cover in European cities could cut the number of heat-related deaths during summer months by nearly 40 per cent." In Columbia's Medellín, creating 30 Green Corridors helped to reduce temperatures by 2°C in the first three years of the program.

Learn more about the heat island effect on the EPA site.

Heat islands

A swan in Europe was a white swan. So, naturally, swans were thought of as only white by Europeans until news came from travelers to Australia in the late 1600s where black swans are in fact relatively common. Black swan events can turn a worldview upside down. They are unprecedented, unexpected, rare, and with a significant impact.

The infrequency of black swan events means prior data about them is too little to reliably guess the likelihood of one, and you may not even think to anticipate the event anyway. Except after the fact, when all of a sudden many people will claim to have predicted it — black swan events are prone to be rationalised in hindsight, believing that all the signs were there beforehand even if they weren't.

The idea of black swan events is from Nassim Nicholas Taleb. He writes:

"One single observation can invalidate a general statement derived from millennia of confirmatory sightings of millions of white swans. All you need is one single black bird."

Examples Taleb gives include the September 11 terrorist attack, the 2008 financial crisis, World War I, or the rise of the Internet.

More Taleb sketches: on mistakes, the firehouse effect, and the Lucretius problem. Also, hindsight bias.

Black swan events

Happy talk: fluff and often self-congratulatory promotional talk usually intended to be friendly but generally just getting in the way of people trying to get a job done. On the web, and to be honest most places, happy talk must die.

Happy talk must die is a gem from Steve Krug's legendary book on usability Don't Make me Think. Here's an excerpt on happy talk.

Also in Don't make me think: Omit needless words

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Happy talk must die