The IPCC's Special Report on Climate Change and Land addresses the closely coupled relationship between land use and climate change. The report notes the climate change mitigation potential of dietary shifts and afforestation. Here, we briefly discuss how decreases in ruminant meat consumption associated with dietary shifts have the potential to free up area for forests, allowing for greater CO₂ sequestration and benefiting biodiversity, while simultaneously reducing anthropogenic CO₂ emissions.

A new conceptual framework is proposed to improve our understanding of soil organic matter behaviour at depth: at any soil profile, two vertically distinct, dynamic zones of influence can be identified, an upper vegetation zone of influence (VZI), controlled by plant traits, and a lower mineral matrix zone of influence (MMZI), controlled by geochemical interactions. In the VZI, soil organic carbon (SOC) flux is upwards to the atmosphere (SOC mineralization to CO₂), while in the MMZI, the SOC flux is downwards to deep soil storage (SOC stabilization and persistence), as it is suggested by SOC profiles in analogy to the ‘zero-flux plane’ concept in hydrology.

One important lever plants use to adjust water demand to local water availability is through changing carbon allocation to leaf area relative to water transport tissue area in the stem. This is because leaf area to stem area regulates water demand from leaves relative to supply capacity by the stem. In this review, we examine vegetation model representations of plant allocation to leaves, how allocation impacts mechanistic model-derived estimates of productivity, and methods for moving forward with representing allocation as an emergent property of scarce resource constraints in trait-based vegetation models.

We found that increasing the input of desalination plant discharge into the Persian Gulf may have the following impacts: alter phytoplankton photosynthesis; increase benthic mortality; change chloroplast ultrastructure, decrease in chlorophyll content, enzyme activity, and electron flow inhibition in photosynthetic organisms; alter larval development and individual growth, larval survival rate and generation time; and result in a loss of fishery resources and economic activity. Furthermore, available data suggest that appropriately sited, designed, and operated desalination plants combined with current developments in impingement and entrainment reduction technology can mitigate many of negative ecological impacts of desalination plants.

We introduce a framework to forecast exposure to climate change at the intraspecific level. We combined correlative species distribution models, a model of species range dynamics, and a model of phylogeographic interpolation. We applied the framework to 20 Iberian amphibian and reptile species. We found that about 80% of the studied species are predicted to contract their range. Within each species, some lineages were predicted to contract their range, while others were predicted to maintain or expand it. Therefore, estimating the impacts of climate change at the species level only can underestimate losses at the intraspecific level.

Already today the European spruce bark beetle Ips typographus is the most significant forest pest insect in Central Europe. We predict that climate change will increase the number of annual beetle generations, particularly at low elevations, and will pre-shift spring swarming, particularly at higher elevations. Altogether, these changes will result in a higher risk of mass infestations in European spruce forests.

Explaining interspecific variation in autumn bird migration phenology trends has been challenging. We performed a spatially explicit time window analysis of weather effects on mean autumn passage of four trans-Saharan and six intra-European passerines at the island of Heligoland (Germany) over a 55-year period (1960–2014). Weather variables at the breeding and stopover grounds explained up to 80% of the species-specific interannual variability in autumn passage. Overall, wind conditions were most important, but the climatic contributions to the temporal trend in autumn migration phenology consisted of a potpourri of wind, precipitation and temperature effects.

The timing of reproduction is a critical component of how free-living organisms respond to ongoing climate change, especially in the Arctic, which is disproportionally impacted by climate warming. Arctic seabirds respond to climate change by moving the start of their reproduction earlier, coincident with an advancing onset of spring, but their response is dependent on the ocean basin and foraging strategy. Surface-feeding species advanced their reproduction in the last 35 years while diving species showed remarkably stable breeding timing. The earlier reproduction for Arctic surface-feeding birds was significant in the Pacific only, where the spring advancement was most pronounced.

This elaborate asset of net accretion rates of the shallow (5 and 10 m depth) leeward coral reefs of Bonaire shows extreme spatial heterogeneity among 115 sites (points). The majority of the fringing reef – which allegedly ranks among the healthiest in the Caribbean – is, however, defined by a limited capacity to maintain structural integrity or to keep pace with projections of sea-level rise (RCP lines), thus posing a threat to ecological functioning, biodiversity and the ecosystem services it sustains. These observations suggest that only protection and restoration of framework building coral assemblages may avert future large-scale submergence of Caribbean reefs.

We characterized the crystallography and carbon uptake in the shells of the oyster Saccostrea glomerata being farmed in habitats subjected to acidification from land run-off using high-resolution electron backscatter diffraction and carbon isotope analyses (δ¹³C). Environmental carbon was linked with the changing carbon in the shell and differences in shell growth and crystallography across oyster families selectively bred for fast growth or disease resistance. We show that these oyster families can alter their mechanisms of biomineralization, promoting resilience to coastal acidification. Selective breeding in oysters is likely to be an important global mitigation strategy for sustainable aquaculture.

Warming of the Arctic has led to changes in multiple environmental factors that control the carbon isotope ratio at the base of the food web. Here, we present the first comprehensive spatial and temporal assessment of the carbon isotopic baseline for the Arctic Ocean, which is essential for understanding and predicting changes in Arctic food web structure. The response of the Arctic ecosystem to ongoing environmental change presented here is stronger than we would predict theoretically.

Multiple interactions between climate, fishing pressure and biogeochemical variables were associated with a high number of synergistic interactions for coral reef communities. Hard corals and coralline algae abundance were generally sensitive to changing environmental conditions where interactions decreased their percentage cover. These synergistic interactions suggest that the negative effects of fishing pressure and eutrophication may exacerbate the impact of climate change on corals. Artist Credit: Ivan Gromicho.

We examined the spatial patterning of thermal tolerance and the strength of phenotypic plasticity across a large latitudinal thermal gradient in a widespread copepod taxon. Population genetic analyses suggest that both gene flow and adaptation play important roles in shaping these patterns, and therefore, in determining vulnerability to climate change. Local adaptation, plasticity, and gene flow should all be considered when making predictions about the future of marine systems.

The combined effects of elevated CO₂ and hypoxia on faunal-mediated carbon fluxes in marine soft sediments are still largely unknown. We used isotopically labelled algal detritus, a common source of organic matter supplied in coastal ocean, to assess carbon incorporation in faunal tissue and in sediment under different experimental conditions. We found that hypoxia hindered the increased carbon uptake by fauna observed at elevated CO₂, limiting the ability of benthic communities to withstand future ocean acidification scenario. In addition, both hypoxia and elevated CO₂ increased sediment carbon burial, likely due to the modifications of faunal-mediated pathways and resource quality.

Little is known about compensatory processes shaping regional differences in organismal vulnerability. We examined large-scale spatial variations in biomineralization under heterogeneous environmental gradients across a 30° latitudinal range in critical foundation species, the blue mussels Mytilus edulis and M. trossulus. Salinity was the best predictor of within-region differences in mussel shell deposition, mineral and organic composition. We identified biomineralization plasticity as a potential compensatory mechanism conferring Mytilus species a protective capacity for quantitative and qualitative trade-offs in shell deposition as a response to regional alterations of abiotic and biotic conditions in future environments.

The illustration shows how Artificial Light Pollution at Night (ALAN) can impact coral reefs by causing different physiological responses leading to photosynthetic performances and increasing oxidative stress.

Climate change research predicting marine species' range shifts has mainly focused on expected responses to changing ocean temperatures, overlooking how other environmental covariates could affect future distribution patterns. We explore how this emphasis on ocean temperature could impact species' climate vulnerability assessments, comparing outputs from temperature-based habitat suitability models to those that include multiple environmental covariates. We find that multifactor models perform better in explaining and predicting species' historical distribution patterns. These models also make more concerning projections for species' future distribution patterns, that is, that species' ranges will largely shift northward and become more contracted and fragmented over time.

In the Neoartic realm, freshwater fish communities are homogenizing. We investigated the role of two major drivers of the recent changes in the structure of freshwater fish communities: recreational fishing versus climate change. The most important finding of our work is that while climate change and species thermal preferences poorly explain recent compositional shifts, we observed a striking contrast between gamefish and baitfish species. While the former thrives, the latter declines leading to a strong homogenization dominated by the colonization of gamefish species.

The total methane (CH₄) emission from various types of surface waters of Berlin, Germany, is 2.6 ± 1.7 Gg CH₄/year. CH₄ fluxes to atmosphere from urban freshwaters are higher than those from similar pristine water bodies. Urban ponds presented the highest CH₄ fluxes.

Ancient plant DNA in a lake sediment record from the Eastern Canadian Arctic constrains postglacial colonization of dwarf birch to 5,900 years ago, which was ~3,000 years after local deglaciation and at least 1,300 years after other tundra plants were established. We place this vegetation history into a climatic context using lipid biomarker paleothermometry, demonstrating that Betula colonization was delayed relative to peak postglacial warmth. This colonization timing is >2,000 years after birch pollen appears in adjacent lake sediment, highlighting the influence of exotic pollen fluxes on palynological records and underscoring the utility of sedimentary DNA for determining local plant presence.

Millions of hectares of degraded land in the tropics and subtropics are targeted for restoration with tree plantations. To assess whether this might be best achieved with mixed-species plantations, we analysed the effects of species diversity and structural diversity on productivity and its temporal stability in the oldest tropical tree diversity experiment. At the tree neighbourhood- and community-level, diversity enhanced productivity and its stability in mixed compared to monospecific stands. Beneficial diversity effects increased with stand development and were highest at the highest levels of diversity and strongest under drought conditions.

We present clearer, stronger, and multitiered evidence to support the novel conclusion that newer and select maize, wheat, and rice varieties developed in China help mitigate N footprint while producing more grains. Individual varieties differed markedly in yield- emission scores. A nationwide farmer survey (2.47 million responses) indicated tremendous opportunities for a new way of management intervention. Coupling variety selection with sound N and other agronomic management can help lower N footprint while producing more grain.

In this study, we found that the advancing leaf-out was accompanied by a shortening length of temperature-relevant period (TRP) in six dominant tree species mainly located in central Europe during 1951–2016. We tested different hypotheses, and found that the advanced leaf-out and unchanged start of TRP might be explained by sufficient chilling and faster accumulation of the required heat due to climatic warming, which overcompensated for the retarding effect of shortening daylength on bud development. These results implicate that phenology modules in global land surface models might be reliable assuming a fixed TRP starting date at least for temperate central Europe.

We undertook a systematic review to examine the influence of land-use and land-cover change (LULCC) on mangrove carbon stocks and soil greenhouse gas effluxes. A search of 478 data points from peer-reviewed literature revealed a substantial reduction of biomass (82% ± 35%) and soil (54% ± 13%) carbon stocks due to LULCC. The relative loss depended on LULCC type, time since LULCC and geographical and climatic conditions of sites. Regeneration efforts (i.e. restoration, rehabilitation and plantation) led to biomass recovery after ~40 years. However, we found no clear patterns of mangrove soil carbon stocks re-establishment following biomass recovery.

We found that plant community composition at landscape scales has shifted in response to warming temperatures and increased precipitation during the 20th century, with other major drivers of global change affecting the occurrence and magnitude of these shifts. Colonizations by warm-adapted species, particularly non-natives, have contributed to community-level warming, at the expense of species more poorly adapted to the direction of climate change. However, widespread landscape simplification in the form of increased forest cover appears to have had a buffering effect on community shifts following climate warming.

Mangroves play an important role in climate change mitigation via coastline protection and carbon burial. Examining recently established, non-native mangrove stands in Hawai‘i, we show that mangrove forests accrue substantial carbon stocks within several decades after introduction. Mangrove establishment results in a significant net removal of greenhouse gases from the atmosphere and also increases shore height faster than sea level rise, impacts that should be considered during decision-making for mangrove management.

Ozone is the most damaging air pollutant to crops, currently reducing Midwest US maize production by up to 10%. In this study, 10 diverse inbred parents were crossed in a half-diallel design to create 45 F1 hybrids, which were tested for ozone response in the field using Free Air Concentration Enrichment (FACE). Ozone stress increased the heritability of photosynthetic traits and altered genetic correlations among traits. FACE technology was essential to this evaluation because genetic variation in photosynthesis under elevated ozone was not predictable based on performance at ambient ozone.

Twenty-first-century climate change will reduce the resilience of Brazil's Araucaria tree (Araucaria angustifolia), with small-scale topographic microrefugia becoming key to its persistence. However, more than a third of these have already lost their natural vegetation, and only 2.5% of what remains is in any protected area.

High-intensity heat waves imposed on field-grown soybean during key reproductive stages reduced seed yield, even under elevated [CO₂]. However, low-intensity heat waves increased yield with greater increases in elevated [CO₂] than in ambient [CO₂] conditions. Differences between measured yields and simulated yields based on carbon assimilation alone suggest that direct heat stress on reproductive processes played a role in determining actual yields.

Experimental nitrogen deposition (ca. 20 years) has slowed fine root decay and increased soil carbon across a widespread northern hardwood forest ecosystem, but the microbial mechanisms underlying this response are unknown. Here, we show that experimental N deposition has reduced the relative abundance of ligninolytic fungi and increased that of bacteria with weaker ligninolytic capacity on decaying fine root litter. These responses are correlated with an accumulation of lignin-derived compounds in soil organic matter, of which fine root litter is the primary source. Thus, anthropogenic nitrogen deposition may enhance terrestrial carbon storage by altering microbial community composition on decaying fine roots.

Warming, accompanied by enhanced growth of deep-rooted grasses, is shown to cause substantial changes in subsoil carbon dynamics of a Qinghai-Tibetan grassland. Subsoils under warming show new carbon accumulation in the silt-clay fraction, increased concentrations of sugars and lipids as well as enhanced degradation of lignin likely due to labile-carbon-stimulated cometabolism. The above shifts stand in contrast to the unaltered belowground net primary productivity and soil carbon dynamics in the topsoil, underscoring the high sensitivity of deep soil carbon cycling to warming in the alpine grassland.