Journal Paper Digests

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Journal Paper Digests 2020 #6

  • Which practices co-deliver food security, climate change mitigation and adaptation, and combat land degradation and desertification?
  • Global patterns of terrestrial nitrogen and phosphorus limitation
  • Mapping soil organic carbon and clay using remote sensing to predict soil workability for enhanced climate change adaptation
  • Modelling the spatial extent and severity of extreme European windstorms

Which practices co-deliver food security, climate change mitigation and adaptation, and combat land degradation and desertification?

By:Smith, P (Smith, Pete)[ 1 ] ; Calvin, K (Calvin, Katherine)[ 2 ] ; Nkem, J (Nkem, Johnson)[ 3 ] ; Campbell, D (Campbell, Donovan)[ 4 ] ; Cherubini, F (Cherubini, Francesco)[ 5 ] ; Grassi, G (Grassi, Giacomo)[ 6 ] ; Korotkov, V (Korotkov, Vladimir)[ 7 ] ; Hoang, AL (Anh Le Hoang)[ 8 ] ; Lwasa, S (Lwasa, Shuaib)[ 9 ] ; McElwee, P (McElwee, Pamela)[ 10 ] …More

View Web of Science ResearcherID and ORCID GLOBAL CHANGE BIOLOGY

Pages: NIL_1-NIL_44 Published: DEC 14 2019

Document Type: Article

Abstract There is a clear need for transformative change in the land management and food production sectors to address the global land challenges of climate change mitigation, climate change adaptation, combatting land degradation and desertification, and delivering food security (referred to hereafter as “land challenges”). We assess the potential for 40 practices to address these land challenges and find that: Nine options deliver medium to large benefits for all four land challenges. A further two options have no global estimates for adaptation, but have medium to large benefits for all other land challenges. Five options have large mitigation potential (>3 Gt CO(2)eq/year) without adverse impacts on the other land challenges. Five options have moderate mitigation potential, with no adverse impacts on the other land challenges. Sixteen practices have large adaptation potential (>25 million people benefit), without adverse side effects on other land challenges. Most practices can be applied without competing for available land. However, seven options could result in competition for land. A large number of practices do not require dedicated land, including several land management options, all value chain options, and all risk management options. Four options could greatly increase competition for land if applied at a large scale, though the impact is scale and context specific, highlighting the need for safeguards to ensure that expansion of land for mitigation does not impact natural systems and food security. A number of practices, such as increased food productivity, dietary change and reduced food loss and waste, can reduce demand for land conversion, thereby potentially freeing-up land and creating opportunities for enhanced implementation of other practices, making them important components of portfolios of practices to address the combined land challenges.

Global patterns of terrestrial nitrogen and phosphorus limitation

By:Du, EZ (Du, Enzai)[ 1,2,3 ] ; Terrer, C (Terrer, Cesar)[ 3,4 ] ; Pellegrini, AFA (Pellegrini, Adam F. A.)[ 3 ] ; Ahlstrom, A (Ahlstrom, Anders)[ 3,5,6 ] ; van Lissa, CJ (van Lissa, Caspar J.)[ 7 ] ; Zhao, X (Zhao, Xia)[ 8 ] ; Xia, N (Xia, Nan)[ 2 ] ; Wu, XH (Wu, Xinhui)[ 2 ] ; Jackson, RB (Jackson, Robert B.)[ 3,9,10 ]

View Web of Science ResearcherID and ORCID NATURE GEOSCIENCE

Volume: 13 Issue: 3 Pages: 221-+ Published: MAR 2020

Document Type: Article

Abstract Spatial patterns in the phosphorus and nitrogen limitation in natural terrestrial ecosystems are reported from analysis of a global database of the resorption efficiency of nutrients by leaves.

Nitrogen (N) and phosphorus (P) limitation constrains the magnitude of terrestrial carbon uptake in response to elevated carbon dioxide and climate change. However, global maps of nutrient limitation are still lacking. Here we examined global N and P limitation using the ratio of site-averaged leaf N and P resorption efficiencies of the dominant species across 171 sites. We evaluated our predictions using a global database of N- and P-limitation experiments based on nutrient additions at 106 and 53 sites, respectively. Globally, we found a shift from relative P to N limitation for both higher latitudes and precipitation seasonality and lower mean annual temperature, temperature seasonality, mean annual precipitation and soil clay fraction. Excluding cropland, urban and glacial areas, we estimate that 18% of the natural terrestrial land area is significantly limited by N, whereas 43% is relatively P limited. The remaining 39% of the natural terrestrial land area could be co-limited by N and P or weakly limited by either nutrient alone. This work provides both a new framework for testing nutrient limitation and a benchmark of N and P limitation for models to constrain predictions of the terrestrial carbon sink.

Mapping soil organic carbon and clay using remote sensing to predict soil workability for enhanced climate change adaptation

By:Paul, SS (Paul, S. S.)[ 1 ] ; Coops, NC (Coops, N. C.)[ 2 ] ; Johnson, MS (Johnson, M. S.)[ 3 ] ; Krzic, M (Krzic, M.)[ 1,4 ] ; Chandna, A (Chandna, A.)[ 1 ] ; Smukler, SM (Smukler, S. M.)[ 1 ]

GEODERMA

Volume: 363 Pages: 14177-14177 Published: APR 1 2020

Document Type: Article

Abstract Climate change is presenting sizeable challenges for agricultural production around the world. In some regions, shifting precipitation patterns in the spring and fall are negatively impacting farm operation by reducing the number of “workable days” or the days fields can be worked with heavy equipment without damaging soil structure. This can be particularly problematic for farms on clay soils and/or poor drainage. Approximating a water content threshold at which a soil is not workable due to soil structure destruction can be helpful for planning effective farm operations. In this study, we applied advanced remote sensing and machine learning tools to produce digital maps of soil organic carbon (SOC) and clay (CL) content and used them in existing pedotransfer functions (PTFs) to predict a workability threshold (WT) across a study area in Delta, British Columbia, Canada. We combined field data, soil and vegetation indices derived from multiple Landsat satellite images, topographic indices, and soil survey information to digitally map SOC and CL of the agricultural lands in Delta using random forest (RF) and generalized boosted regression model (GBM). When validated against an independent field dataset, the RF model outperformed GBM for all accuracy measures (coefficient of determination - R-2, concordance correlation coefficient - CCC, and normalized root mean square error - nRMSE). We then spatially applied several PTFs using our digital maps to estimate the plasticity limits of the soil and produce WT map. The WT map was then tested against independent field samples of the soil water content at - 10 kPa and we achieved R-2 of 0.59, CCC of 0.70, and nRMSE of 0.15. Our analysis showed that 40% of the fields in the study area had WT < 30%, a threshold that is already being impacted by reduced workable days. This WT map could be used to improve spatial prioritizations of investments for climate change adaptation at farm to regional scales.

Modelling the spatial extent and severity of extreme European windstorms

By:Sharkey, P (Sharkey, Paul)[ 1 ] ; Tawn, JA (Tawn, Jonathan A.)[ 2 ] ; Brown, SJ (Brown, Simon J.)[ 3 ]

JOURNAL OF THE ROYAL STATISTICAL SOCIETY SERIES C-APPLIED STATISTICS

Volume: 69 Issue: 2 Pages: 223-250 Published: APR 2020

Document Type: Article

Abstract Windstorms are a primary natural hazard affecting Europe that are commonly linked to substantial property and infrastructural damage and are responsible for the largest spatially aggregated financial losses. Such extreme winds are typically generated by extratropical cyclone systems originating in the North Atlantic and passing over Europe. Previous statistical studies tend to model extreme winds at a given set of sites, corresponding to inference in an Eulerian framework. Such inference cannot incorporate knowledge of the life cycle and progression of extratropical cyclones across the region and is forced to make restrictive assumptions about the extremal dependence structure. We take an entirely different approach which overcomes these limitations by working in a Lagrangian framework. Specifically, we model the development of windstorms over time, preserving the physical characteristics linking the windstorm and the cyclone track, the path of local vorticity maxima, and make a key finding that the spatial extent of extratropical windstorms becomes more localized as its magnitude increases irrespective of the location of the storm track. Our model allows simulation of synthetic windstorm events to derive the joint distributional features over any set of sites giving physically consistent extrapolations to rarer events. From such simulations improved estimates of this hazard can be achieved in terms of both intensity and area affected.

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