How climate change is knocking natural events wildly out of sync

Climate change is throwing off the timing of key events in the natural world, from the flowering of plants to the migrations of birds and mammals. Now, ecologists are warning that this could spiral out of control and cause whole ecosystems to break down

By Graham Lawton

EVERY year in early spring, Japan goes blooming crazy. The first cherry blossoms open in Okinawa in the south in February and the spectacle reaches Tokyo a few weeks later. For the brief period when the trees are in bloom, people gather under the their beautiful pink and white canopies for hanami, the traditional custom of flower viewing. It sounds genteel, but wild parties are known to break out.

Hanami has been taking place since the 8th century, but the historical records tell a curious story. For the best part of 1000 years, hanami in Tokyo and Kyoto reliably occurred in the second week of April. By the 1830s, however, it had begun to shift earlier. Last year, Kyoto recorded its earliest-ever full bloom, on 26 March.

The cause of this moveable feast is climate change. Cherry trees open their flowers in response to a few consecutive days of springtime warmth, which is arriving ever sooner. Early flowering brings the risk of a sudden frost, which can kill off the blooms – and the celebrations.

But what’s at play here is much more than an inconvenience for hanami-goers. Similar time shifts are occurring throughout the world with increasingly disruptive effects. “Timing is everything for ecosystem harmony,” says Maarten Kappelle at the UN Environment Programme (UNEP) in Nairobi, Kenya. Although these shifts have been apparent for years, Kappelle and others are warning that the disruption now threatens to completely break down ecosystems, leading to catastrophic losses of species and compromised food security. So how badly out of sync is nature – and can we do anything about it?

Natural historians have long …