Forests around the world, widely deemed the lungs of the planet, “held their breath” during the most recent episode of a so-called climate change hiatus, a new study has revealed. The findings are considered significant in predicting how ecosystems will react to rising global temperatures.
A team from the University of Exeter in the United Kingdom showed that the global carbon sink — a forest, ocean, or another natural environment that can absorb carbon dioxide from the atmosphere — was specifically strong from 1998 to 2012, a period of 14 years deemed as a warming pause.
During this time when slower warming occurred, forests worldwide “breathed in” CO2 through the process of photosynthesis, but exhibited a reduced rate of “breathing out” or releasing the gas back into the atmosphere.
Global Carbon Sink
“In this study, we analyzed what happened during the recent period of reduced warming, the so-called hiatus, highlighting the importance of ecosystem respiration as a key control of land carbon sinks,” explained professor and lead researcher Pierre Friedlingstein in a statement.
Earth’s natural ecosystems, including these forests, are believed to counter the adverse impacts of fossil fuel use through removing CO2 from the atmosphere and serving as a carbon sink. It remains uncertain, though, how they will act on future climate change: will they consume more carbon or release more volumes of it back into the environment?
In the study, the total CO2 amount gobbled up by forests slowed during times when warming is rapid, and accelerated during slower warming periods. Photosynthesis also remained constant during slower warming, but the forests emitted less carbon back into the surroundings.
This means the planet stores much more carbon during these periods of hiatus, the team concluded. The carbon sink of the world emerged as “surprisingly strong,” as if forests held their breath.
The findings were discussed in the journal Nature Climate Change.
No Actual Warming Pause?
Speculations of a warming pause are fueled by data showing that from 1998 to 2012, global temperature rise appeared to plateau, based on NOAA’s Extended Reconstruction Sea Surface Temperature dataset. This hiatus has divided scientists and promoted skeptics to believe that man-made climate change is a hoax.
A study earlier this month concluded that no actual hiatus likely occurred, with the oceans steadily warming over the past 50 years. The team led by University of California Berkeley’s Zeke Hausfather saw further evidence that confirmed ocean temperatures’ stable warming without any pronounced slowdown.
They pointed to issues in ocean measurements — including a cooling bias in a previous dataset version that lowered global temperatures than actual — and not a slowdown.
Whatever pause took place in the 2000s, it seems to have ended by now, with the years 2014 to 2016 breaking records as the warmest years on modern temperature record. In the United States alone, 2016 ranked second hottest in record since 1895, with every single state and city within the Lower 48 states logging higher temperatures than usual last year.
The NOAA dubbed 2016 “a year of temperature and precipitation extremes” in the country.
