Editing IPCC:AR6/WGI/TS (section)

=== Selected Updates and/or New Results Since AR5, SRCCL and SROCC ===

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* '''Atmospheric concentration of methane:''' The SRCCL reported a resumption of atmospheric CH <sub>4</sub> concentration growth since 2007. The AR6 reports a faster growth over 2014–2019 and assesses growth since 2007 to be largely driven by emissions from the fossil fuels and agriculture (dominated by livestock) sectors. (Section TS.2.2)
* '''Land and ocean carbon sinks:''' The SRCCL assessed that the persistence of the land carbon sink is uncertain due to climate change. The AR6 finds that land and ocean carbon sinks are projected to continue to grow until 2100 with increasing atmospheric concentrations of CO <sub>2</sub> , but the fraction of emissions taken up by land and ocean is expected to decline as the CO <sub>2</sub> concentration increases, with a much larger uncertainty range for the land sink. The AR5, SR1.5 and SRCCL assessed carbon dioxide removal options and scenarios. The AR6 finds that the carbon cycle response is asymmetric for pulse emissions or removals, which means that CO <sub>2</sub> emissions would be more effective at raising atmospheric CO <sub>2</sub> than CO <sub>2</sub> removals are at lowering atmospheric CO <sub>2</sub> . (Section TS.3.3, Box TS.5)
* '''Ocean stratification increase''' '''[[#footnote-009|12]]''' ''':''' Refined analyses of available observations in the AR6 lead to a reassessment of the rate of increase of the global stratification in the upper 200 m to be double that estimated in SROCC from 1970 to 2018. (Section TS.2.4)
* '''Projected ocean oxygen loss:''' Future subsurface oxygen decline in new projections assessed in WGI AR6 is substantially greater in 2080–2099 than assessed in SROCC. (Section TS.2.4)
* '''Ice loss from glaciers and ice sheets:''' Since SROCC, globally resolved glacier changes have improved estimates of glacier mass loss over the past 20 years, and estimates of the Greenland and Antarctic Ice Sheet loss have been extended to 2020. (Section TS.2.5)
* '''Observed global mean sea level change:''' new observation-based estimates published since SROCC lead to an assessed sea level rise estimate from 1901 to 2018 that is now consistent with the sum of individual components and consistent with closure of the global energy budget. (Box TS.4)
* '''Projected global mean sea level change:''' The AR6 projections of global mean sea level are based on projections from ocean thermal expansion and land ice contribution estimates, which are consistent with the assessed ECS and assessed changes in global surface temperature. They are underpinned by new land ice model intercomparisons and consideration of processes associated with ''l'' ''ow confidence'' to characterize the deep uncertainty in future ice loss from Antarctica. The AR6 projections based on new models and methods are broadly consistent with SROCC findings. (Box TS.4)

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