On June 6, 1857, Henry David Thoreau wrote this in his journal: “Our thoughts and sentiments answer to the revolutions of the seasons, as two cog-wheels fit into each other.” It’s true: the seasons we know are both material and cultural, both collective and personal. We expect them to stay reasonably stable through our lifetimes and we layer them with all kinds of memories and expectations. 

The June solstice will arrive as usual on the 20th, despite our having caused Earth’s axis to move a little bit (through climate change and perhaps groundwater pumping). But – as a direct result of our putting more CO2 into the air – other aspects of our seasons are breaking with their past. 

We’ll focus first on the planet’s temperate zones.

According to the American Geophysical Union (AGU), “Northern Hemisphere summers may last nearly half the year by 2100.” Note the excellent graphic of the projected shifting of season dates.

You can find an excellent set of summaries and specific data (intended for reporters) at Climate Central and at the EPA’s newly-restored set of climate indicators (see seasonal temperatures and growing seasons).

Winters are warmer, even when they seem cold to us, as explained by Mark Kaufman in Mashable

Springs are earlier. See, for instance, this story (Jason Samenow, Washington Post) about Japan’s cherry blossom records and this EPA record of ice breakup on Alaska’s rivers. 

As many of us know in our own bodies, allergy seasons are lengthening. This 2021 story in Vox by Umain Irfan is an excellent explanation. (Additional explanations and graphics are in Irfan’s 2020 piece.) For more on the new study led by William Anderegg, see John Schwartz in the NYT here.

Fire weather seasons are starting earlier and lasting longer, as explained (in April 2021) here by Simon Romero in the NYT and (in 2015) here by NASA.

California offers an especially vivid example of how changing seasons and wildfire intersect (Matthew Cappucci, Washington Post), with its Mediterranean climate characterized by wet and dry seasons. Similar changes are projected for the Mediterranean itself, as explained in this report from McKinsey

What about the parts of the world where monsoons dominate the seasons? Though nearly two-thirds of all people live in such places, the  mechanisms of current and expected changes are not well understood. It does seem clear that monsoons will continue to grow stronger and more erratic (thus causing significantly more chaos). You can learn more in these stories (focused on India): 


This series is curated and written by retired Colorado State University English professor and close climate change watcher SueEllen Campbell of Colorado. To flag works you think warrant attention, send an e-mail to her any time. Let us hear from you.

SueEllen Campbell

SueEllen Campbell created and for over a decade curated the website "100 Views of Climate Change," a multidisciplinary collection of pieces accessible to interested non-specialists. She is especially interested...