You write seasons are changing in the Anthropocene — how so?
Because of altered management, this is a land use change impact — land itself begins to generate new seasons. With seasons changing their rhythms, a lot is due to climate change — in Western Europe or North America, summer took three months. This squeezing of seasons — arrhythmia — is due to climate change while emergent seasons are linked to pollution and land management. ■ ‘Phenology’ describes seasonal rhythms in animals and plants, times of the year when they nest or migrate, flower or are dormant, when animals seek food or sleep. Because of this need for reliable electricity elsewhere, hydropower protects urban citizens but the seasonal lives of downstream communities change.
Such fires would not have happened before such agriculture. So, you’ve now got this human impact, combining with El Nino and La Nina, producing smoke every year. Several emergent seasons in our research are associated with air pollution — northern Thailand’s smoky season is linked to agricultural fires. Delhi’s smog, linked to cars and industry, is also connected to agricultural burning which happens at a particular time of year. It now feels like six months — spring seems very short before it transitions into hot weather. Autumn comes later and, in many places, people lament the loss of winter — it doesn’t snow, there’s no frost. Shifting seasons drive those phenological cycles out of sync, causing ecosystem problems — imagine one species consuming another to survive. In ecosystems, the natural balance gets shaken with seasonal arrhythmia. We also found multiple sequential impacts on human communities. In rural Thailand, communities once thrived on shrimp farming in the wet months and rice cultivation in the dry season. The building of dams affects those seasonal rhythms — then, you introduce industrial agriculture, like maize, which requires burning and generates air pollution. That affects health and rain. Meanwhile, people in cities rely on electricity from dams, which grows more pressing as it becomes hotter and more polluted.
If the latter flourishes earlier in the year, that food will no longer be available.
■ I and my co-author, Felicia Liu, researched how seasonality is evolving with rapid human-driven change on Earth. We worked in Southeast Asia where we noticed people call a part of the year ‘the haze season’, when smoke arrives routinely in Malaysia and Singapore. So, we began thinking about ‘emergent seasons’ in the Anthropocene and, studying environmental data, satellite information, etc., we found quite a few. We then began thinking if some seasons are appearing, perhaps some are disappearing. We termed those ‘extinct seasons’ — the most familiar would be the loss of winter sports season. We also found some seasons getting longer, some shorter, some becoming more or less intense. We call these ‘arrhythmic’ or ‘syncopated’ seasons, which draws from a musical metaphor where beats become more prominent and start drawing the listener’s attention. These are the four types — emergent, extinct, arrhythmic and syncopated.
This is a new time — it didn’t exist before the 1980s.
