Snapshots Of Weather Extremes Don’t Paint The Full Picture Of Climate Change

Weather phenomena such as extreme cold periods or air pollution have been captured in paintings and (later) photos for centuries. But although these images form an interesting record of local climates of the past, individual pictures often don’t tell the full story.

Scrolling through Instagram this winter I admired some of the stunning winter shots that friends in Canada had taken. They got a huge amount of snow within days, covering everything in sight in several inches of white powder. Meanwhile, in London, England, we haven’t seen a single snowflake all season. 

But photos are just a snapshot – and not just literally. This same winter that Toronto saw an unusually large amount of snow, data from Environment Canada (visualised by Rolf Campbell)  suggested that the city is in fact getting gradually warmer. For only the second time in recorded history, Toronto had gone an entire year without temperatures dropping below -14°C (6.8°F) and the four years with the highest minimum temperatures were all within the last two decades. Even though temperatures dropped well below -14°C as soon as the calendar turned to 2022, it’s a stark reminder that a brief moment of cold and snow doesn’t necessarily mean that climate change isn’t gradually happening in the background. 

The same is true for the “Little Ice Age”, a famous period of long cold winters from about the 16th to 19th century. These cold winters were captured in many paintings during that time, by Bruegel, Avercamp, and others.

Thanks to art from that time we’re relatively familiar with the Little Ice Age. However, this familiarity has also led people to speculate that maybe our current warm times aren’t unusual, and that we’re just comparing it to those abnormally cold centuries we know from paintings. But that argument doesn’t hold up once you look beyond the art.

First, the Little Ice Age wasn’t global. According to a study published in Nature in 2019, the Little Ice Age didn’t affect all parts of the world at the same time. Depending on where in the world you looked, the coldest part of it could have been in the 15th century or in the 19th century. That’s remarkably different from climate change, which is happening everywhere all at once, right now – not just on a few continents spread out over centuries. 

Second, the Little Ice Age wasn’t an entirely cold period. In 2017 a paper in Astronomy & Geophysics pointed out  that even though Europe had freezing cold winters during the Little Ice Age period, it also had very hot summers around that time. Those extremes meant that the average annual temperature was only about half a degree (°C) different from the years before and after that period. On the other hand, in the years since the Industrial Revolution the average temperature in Europe has already gone up by 1.3 degrees. It really is getting warmer than it should be, even without considering the Little Ice Age.

But our current global climate change does have something in common with the Little Ice Age years: we can see it in pictures. Just like the cold winters of the past have been immortalized in pictures hanging on the walls of art museums, our photo albums and social media feeds are gradually collecting photographic evidence of climate change. 

For example, according to a study by Cambridge researchers published earlier this month, plants in the UK have been flowering a month earlier than they did during the two centuries prior to the mid-1980s. They based it on a large dataset collected by the Woodland Trust, but if you get the family photo albums out, you might be able to see this change as well. Where you now see buds appearing on trees in March, photos from forty years ago might not have shown them until April.

Of course, these photos would still just be snapshots. Just like snowy pictures from Canada don’t reflect gradually warmer annual temperatures, pictures of early flowers in bloom don’t tell you everything about the climate. But as conditions in the environment change, they will undoubtedly be captured in the images we take of the world around us. Researchers have already tried to establish the former shape of glaciers from old paintings and deduced air quality of the past based on paintings of sunsets.

So, perhaps in a few hundred years researchers might be looking at your Instagram account and your pictures of trees and snow to get a better picture of the climate we have today.