BEIJING, Dec. 24, 2018 (BSS/XINHUA) – Chinese scientists have found the
summer carbon uptake of the terrestrial ecosystem in the northern hemisphere
has been significantly weakened by ongoing climate warming.
In other words, warmer years were associated with lower ecosystem carbon
uptake — the process of removing and capturing carbon from the atmosphere.
Observations of atmospheric carbon dioxide concentration from atmospheric
monitoring stations at high latitudes provide complementary monitoring of the
dynamics of carbon exchange in northern ecosystems.
Most studies of the northern hemisphere carbon cycle based on atmospheric
carbon dioxide concentration have focused on spring and autumn, but the
climate change impact on summer carbon cycle remains unclear.
Summer has the highest vegetation productivity, actively contributes to
year-to-year variations in terrestrial carbon uptake and generally has the
most favorable climatic conditions for carbon dioxide uptake, said the study
published in Nature Communications.
Scientists from the Institute of Tibetan Plateau Research of Chinese
Academy of Sciences used the record of atmospheric carbon dioxide
concentrations to calculate the summer carbon dioxide drawdown, an indicator
of summer carbon uptake, between July and August.
They found that the summer carbon uptake is significantly negatively
correlated with terrestrial temperature within 50 degrees north latitude
year-to-year from 1979 to 2012.
A refined analysis at the decadal scale reveals strong differences between
the earlier (1979-1995) and later (1996-2012) periods, with the significant
negative correlation only in the later period.
The emerging negative temperature response is primarily due to summer
vegetation activities no longer positively responding to temperatures,
according to the scientists.
BSS/XINHUA/GMR/1006 hrs