For thousands of years, our societies have been organized around one assumption: we know when the seasons begin.
Whether it is the four seasons of the temperate regions, the wet and dry seasons of the subtropics, or the six seasons of Indigenous Australians, every society has its own way of understanding the seasonal rhythm.
The fact is that we humans don’t merely live in the seasons. We live by the seasons.
We organise our lives around seasons so naturally that we hardly notice it. School begins with a season.
Holidays belong to a season.
They “tell” trees when to leaf, birds when to migrate, insects when to emerge, and farmers when to sow. Harvest has its season. Even many diseases have their season. Seasons are not just something we experience. They are the invisible rhythm that organises civilisation.
That tells us something remarkable.
For thousands of years, the rhythm of our civilization has been synchronized with the rhythm of nature.
Whatever this rhythm is.
Therefore the first lesson could be: there is no universal calendar of seasons.
Although seasons look different around the world, every society organizes itself around them. Every ecosystem organizes itself around them. Every organism organizes itself around them.
Climate change is not only making our planet warmer.
It is taking away something much more fundamental:
our certainty in the timing and duration of the seasons.
This was the central message of my keynote lecture at the International Congress of Biometeorology.
Over the coming weeks, I will share examples from energy, agriculture, health and tourism, all leading to the same question:
When does a season actually begin and how long will it last?
Because answering that question may become one of the most important climate challenges of the coming decades.