Contrasting responses of autumn-leaf senescence to daytime and night-time warmingWu, Chaoyang; Wang, Xiaoyue; Wang, Huanjiong; Ciais, Philippe; Peñuelas, Josep; Myneni, Ranga; Desai, Ankur; Gough, Christopher; Gonsamo, Alemu; Black, Andrew; Jassal, Rachhpal; Ju, Weimin; Yuan, Wenping; Fu, Yongshuo; Shen, Miaogen; Li, Shihua; Liu, Ronggao; Chen, Jing; Ge, Quansheng
doi: 10.1038/s41558-018-0346-zpmid: N/A
Plant phenology is a sensitive indicator of climate change
1–4
and plays an important role in regulating carbon uptake by plants
5–7
. Previous studies have focused on spring leaf-out by daytime temperature and the onset of snow-melt time
8,9
, but the drivers controlling leaf senescence date (LSD) in autumn remain largely unknown
10–12
. Using long-term ground phenological records (14,536 time series since the 1900s) and satellite greenness observations dating back to the 1980s, we show that rising pre-season maximum daytime (T
day) and minimum night-time (T
night) temperatures had contrasting effects on the timing of autumn LSD in the Northern Hemisphere (> 20° N). If higher T
day leads to an earlier or later LSD, an increase in T
night systematically drives LSD to occur oppositely. Contrasting impacts of daytime and night-time warming on drought stress may be the underlying mechanism. Our LSD model considering these opposite effects improved autumn phenology modelling and predicted an overall earlier autumn LSD by the end of this century compared with traditional projections. These results challenge the notion of prolonged growth under higher autumn temperatures, suggesting instead that leaf senescence in the Northern Hemisphere will begin earlier than currently expected, causing a positive climate feedback.
Coastal wetland management as a contribution to the US National Greenhouse Gas InventoryCrooks, Stephen; Sutton-Grier, Ariana; Troxler, Tiffany; Herold, Nathaniel; Bernal, Blanca; Schile-Beers, Lisa; Wirth, Tom
doi: 10.1038/s41558-018-0345-0pmid: 32601525
The IPCC 2013 Wetlands Supplement provided new guidance for countries on inclusion of wetlands in their National GHG Inventories. The United States has responded by including managed coastal wetlands for the first time in its 2017 GHG Inventory report along with an updated time series in the most recent 2018 submission and plans to update the time series on an annual basis as part of its yearly submission to the United Nations Framework Convention on Climate Change (UNFCCC). The United States followed IPCC Good Practice Guidance when reporting sources and sinks associated with managed coastal wetlands. Here we show that intact vegetated coastal wetlands are a net sink for GHGs. Despite robust regulation that has protected substantial stocks of carbon, the United States continues to lose coastal wetlands to development and the largest loss of wetlands to open water occurs around the Mississippi Delta due mostly to upstream changes in hydrology and sediment delivery, and oil and gas extraction. These processes create GHG emissions. By applying comprehensive Inventory reporting, scientists in the United States have identified opportunities for reducing GHG emissions through restoration of coastal wetlands that also provide many important societal co-benefits.
Limiting fossil fuel production as the next big step in climate policyErickson, Peter; Lazarus, Michael; Piggot, Georgia
doi: 10.1038/s41558-018-0337-0pmid: N/A
Despite the current ambivalence of the United States towards the Paris Agreement, national and local jurisdictions across the globe remain committed, and they are seeking ways to increase the ambition and effectiveness of their climate policies. One way forwards could be limiting the production — not just the consumption — of coal, gas and oil. Here we describe the rationale for, and CO2 emissions implications of, limiting oil production. Seven countries have recently imposed such limits, and we develop a case study for a potential addition to this group, the US state of California. We find that by ceasing the issuance of permits for new oil wells, California could reduce global CO2 emissions substantially and also enhance environmental justice in the state.
The year that wasdoi: 10.1038/s41558-018-0369-5pmid: N/A
The impacts of climate change were again increasingly apparent and the future was emphasized in the IPCC Special Report, yet political change is still lagging.