The rate of phenology over the northern hemisphere slowed down during the warming hiatus between 1998 and 2012, a period when warming paused shortly, according to a study published online in Nature Communications. 

 

In recent years, much attention has been paid to how the warming hiatus has influenced terrestrial ecosystems. A recent study showed that the warming hiatus led to increased net terrestrial carbon absorption during the period due to reduced respiration. A few studies using species-level phenology data at the site scale showed the warming hiatus influenced the phenological trend. However, the impact of the warming hiatus on phenological patterns has not been measured on a global scale.

 

 

“Changes in spring and autumn phenology can differentially alter the growing season length and affect the carbon, water, and energy fluxes between the terrestrial biosphere and the atmosphere,” said Xufeng Wang , lead author of the study from the Northwest Institute of Eco-Environment and Resources (NIEER), Chinese Academy of Sciences (CAS) .

 

In order to understand the relationship between biodiversity and climate variability, phenology should be carefully scrutinized. To analyze phenological patterns in the northern hemisphere before and after the warming hiatus, long-term satellite and FLUXNET records were used. Satellite data showed that the rate of phenology slowed down during the global warming hiatus. The study of FLUXNET observations also showed that there was no overall advancing or delaying patterns in spring and autumn phenology during the warming hiatus. Therefore, to examine the effects on phenology of the warming hiatus (1998-2012), phenology trends in the northern hemisphere before and after were examined. Spring phenology (SOS) significantly advanced before 1998, but had no significant trend after 1998. EOS had a delaying trend before 1998 , but had no trend after 1998, says the article. 

 

According to Li Xin , corresponding author of the study from Institute of Tibetan Plateau Research, Chinese Academy of Sciences , increase in the carbon uptake emerging from the prolongation of the growing season has the potential to alleviate climate change. Therefore, clarifying phenological patterns will contribute to our understanding of the effects of climate change on ecological productivity, carbon cycling and climate feedback. 

 

“It remains unclear when zero carbon emissions will be achieved. Therefore, the stabilization of phenology globally likely can’t be expected for the foreseeable future unless another warming hiatus occurs. Our findings have significant implications for understanding the responses of phenology to climate change and the climate-carbon feedbacks,” said Wang.

 

Editor's note：The study is supported by Pan-TPE, a TPE related science project.