- 1Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Switzerland
- 2Swiss Federal Institute of Aquatic Science and Technology Eawag, Switzerland
- 3Plymouth Marine Laboratory, United Kingdom
- 4Department of Geography, University of Zurich, Switzerland
Emerging evidence suggests that temperature increases due to climate change not only differ strongly between regions but also across seasons. As a rule of thumb, one could argue that colder seasons (e.g., winter) tend to warm up faster than warmer seasons, although there are notable exceptions to this rule (e.g., due to changes in the polar vortex). The implications of such seasonal differences in warming trends for plant phenology, i.e., the timing of key events during the plant seasonal cycle, however remain poorly understood. A gap in knowledge that arises, in part, because we lack a global overview of the period(s) of the year during which changing temperatures impact on the phenological cycle of plants the most.
Here, we provide a global analysis of the interrelationships between seasonal temperature changes and global land surface phenology using satellite data from the period 2001-2019. More specifically, we determined the annual period of highest correlation between temperature fluctuations and the onset of different phenological stages within a 100km radius around 10.000 point locations. We found that, across most of the Northern Hemisphere’s mid and high latitudes, a wide range of these stages, i.e., from the onset of ‘greenup’ to ‘greendown’, correlate strongly with temperature fluctuations during roughly the same period of the year, i.e., up until a few weeks before or after the onset of greenup. We found that warming rates during this period were roughly 1.5-2.5 times faster than regional mean annual temperature increases, which, in turn, were roughly 1.5-2.0 times faster than the increase in global mean annual temperature (which includes air above the oceans).
When assessing the impact of global mean annual temperature changes on global land surface phenology, it is thus crucial to consider seasonal differences in warming. These differences are likely to affect not only plant phenology but also many other key processes related to plant growth and development.
How to cite: Lever, J., Gilarranz, L., D'Odorico, P., Psomas, A., Ginzler, C., Simis, S., Damm, A., Gessler, A., Odermatt, D., and Vitasse, Y.: Seasonal warming and global land surface phenology, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17138, https://doi.org/10.5194/egusphere-egu25-17138, 2025.
