With Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon, we speak today of the seasons that no longer run smoothly.
We saw record temperatures in California a week ago: 30 degrees in February. A heat wave in winter. And this is not an isolated case. With a lag of one month on average, and an imbalance that sets in: summer is getting longer, it could last nearly six months in the northern hemisphere by 2100, and winter less than two month…
franceinfo: Are climatologists measuring that climate change is already having an impact on the seasons?
Mathilde Fontez: A study carried out in the United Kingdom demonstrates this. It has just been published. The researchers collected and analyzed more than 400,000 plant flowering records from across the country. This includes 400 plant species. All between the years 1753 and 2019.
Because, to assess the evolution of the seasons, monitoring temperatures is not enough – here, it is a question of studying the response of ecosystems: how does the environment react to rising temperatures? Is climate change already visible, globally, on a large scale, on plants?
And it shows…
No doubt, yes: the ecologists have separated their sample into two periods: before and after 1986. And they see that the first flowering has advanced by nearly a month on average. A phenomenon which is accentuated in the south of the country: the species flower a week earlier still.
The advance reaches 32 days for the plant species which are the most plastic, these are the ones which adapt genetically the fastest to environmental changes, such as grass for example. Trees and shrubs adapt a little less quickly. But all plant species are affected.
And this ties in with another study that was conducted in Japan last year, on cherry blossom, which is particularly followed in the country. There, the ecologists noted an advance of 10 days.
Winter is getting shorter…
Flowering took place in April. They take place in March today. And the researchers anticipate that this slide will continue. So on the one hand, it’s good news: plants are adapting to warming. But this adaptation remains limited.
There is one factor that does not change, the light they receive, which depends on the height of the Sun in the sky, on the length of the day. It is a story of the position of the Earth in relation to the Sun which is not going to change. Above all, what worries ecologists is the discrepancy between the different components of the ecosystem. Animals do not adapt as quickly to warming as plants.
What is likely to happen is that the pollinators shift in relation to flowering, and more generally that the animals do not find food at the time of their reproduction period.
To quote the researchers: “If plants continue to flower earlier, and if the frequency, intensity and duration of climatic extremes increase further, the functioning and productivity of biological, ecological and agricultural systems will be at their lowest.” So yes, summer is getting longer, winter is getting shorter. But that’s not good news…