Small Spikes Make a Deadly Difference

A 2 ºC rise in global temperatures may not seem huge, until you consider the context and havoc climate change has already wrought.


This week, I learned something about ice ages that re-framed the topic of climate change for me. This one fact changed my perception of the magnitude of the challenges we’re facing: the difference between our global average annual temperature today and what we consider an ice age is only about 5 oC.

That margin feels astoundingly small. Much smaller than I would have guessed.

It feels smaller still considering that the global average temperature has already risen 0.7 oC in the last century alone, which is a meteoric rise compared to anything else we’ve seen in the past million years of paleoclimate data stored in glacial ice. By comparison, rising out of an ice age usually involves a total rise of 4-7 oC spread out over about 5,000 years. That makes regular recovery warming from an ice age about 10 times slower than what we’re experiencing now.

The average temperature on Earth normally stays within a very narrow window. So when people debate how best to address climate change, setting targets to cap the post-industrial rise in global average temperature at 2 oC, context is important to understanding how monumental this seemingly tiny number actually is.

As University of Waterloo climate scientist Blair Feltmate points out, while any single extreme heat event can’t be directly blamed on climate change, the long-term pattern is undeniable; climate change deniers who argue that particular extreme weather events aren’t linked to climate change ignore the bigger picture. By that logic, no particular home run can be attributed to steroid use, says Feltmate, and so a case against a baseball player on a hitting streak caught doping should be similarly dismissed.

Last year, 2017, saw historic damage from a horrific hurricane season. Earlier this month, a heat wave swept over much of the northern hemisphere, breaking temperature records and stretching on for up to a week; the final death toll reached 54 people in Quebec alone. A third of the world’s population lives in places where daily temperatures are considered lethal on more than 20 days a year, a number that is only projected to rise.

Putting all of this into perspective is the first step in catalyzing social change, and demanding policies that support research and resources to fight the biggest environmental crisis of our time.

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Karyn Ho is a science animator and engineer who thrives at the interface between science, engineering, medicine, and art. She earned her MScBMC (biomedical communications) and PhD (chemical engineering and biomedical engineering) at the University of Toronto. Karyn is passionate about using cutting edge discoveries to create dynamic stories as a way of supporting innovation, collaboration, education, and informed decision making. By translating knowledge into narratives, her vision is to captivate people, spark their curiosity, and motivate them to share what they learned.