Projecting impacts of global climate and land‐use scenarios on plant biodiversity using compositional‐turnover modelling

Abstract

Nations have committed to ambitious conservation targets in response to accelerating rates of global biodiversity loss. Anticipating future impacts is essential to inform policy decisions for achieving these targets, but predictions need to be of sufficiently high spatial resolution to forecast the local effects of global change. As part of the intercomparison of biodiversity and ecosystem services models of the Intergovernmental Science‐Policy Platform on Biodiversity and Ecosystem Services, we present a fine‐resolution assessment of trends in the persistence of global plant biodiversity. We coupled generalized dissimilarity models, fitted to >52 million records of >254 thousand plant species, with the species–area relationship, to estimate the effect of land‐use and climate change on global biodiversity persistence. We estimated that the number of plant species committed to extinction over the long term has increased by 60% globally between 1900 and 2015 (from ~10,000 to ~16,000). This number is projected to decrease slightly by 2050 under the most optimistic scenario of land‐use change and to substantially increase (to ~18,000) under the most pessimistic scenario. This means that, in the absence of climate change, scenarios of sustainable socio‐economic development can potentially bring extinction risk back to pre‐2000 levels. Alarmingly, under all scenarios, the additional impact from climate change might largely surpass that of land‐use change. In this case, the estimated number of species committed to extinction increases by 3.7–4.5 times compared to land‐use‐only projections. African regions (especially central and southern) are expected to suffer some of the highest impacts into the future, while biodiversity decline in Southeast Asia (which has previously been among the highest globally) is projected to slow down. Our results suggest that environmentally sustainable land‐use planning alone might not be sufficient to prevent potentially dramatic biodiversity loss, unless a stabilization of climate to pre‐industrial times is observed.

Projecting terrestrial biodiversity intactness with GLOBIO 4

“…Our scenario projections suggest that land use will also be the most important cause of biodiversity loss in 2050. This is consistent with the projections of Sala (), but in contrast to studies indicating that impacts of climate change on biodiversity may have exceeded land‐use impacts halfway this century (Di Marco et al, ; Newbold, ). It is notoriously difficult to quantify the effects of future climate change in comparison to the impacts of other threats, reflecting model as well as data limitations (Newbold, ; Tingley, Estes, & Wilcove, ).…”

“…Interestingly, the global human population projected for 2050 is highly similar between the sustainability scenario (8.5 billion people) and the fossil‐fuelled development scenario (8.6 billion people; KC & Lutz, ), whereas the latter is characterized by an increase rather than a decline in agricultural land area (+2.5% worldwide; Table S5). The comparison between these two scenarios thus highlights the importance of changes in both production and consumption of agricultural products in order to limit the environmental impacts, in line with the results of other recent studies (Di Marco et al, ; Erb et al, ; Springmann et al, ). Yet, alongside relatively stable or reduced land demand in the sustainability scenario, we found clear increases in the impacts of climate change and road disturbance (Figure ).…”

Sustainable development must account for pandemic risk

“…Similarly, livestock populations are being mapped with increasing accuracy and resolution-spatial extent of pasture areas, change in livestock head counts over time, details of the farming system, etc.-but the relationship of these factors to EID risk is not yet adequately assessed over large scales. One promising avenue for better integrated EID risk research is socioeconomic scenario analysis, which is widely used in sustainability, biodiversity, and agricultural research (6,24). This approach-which entails projecting the response of biological and socioeconomic systems to changing environmental conditions-could be built into environmental and social safeguard frameworks, to better anticipate and mitigate the risks and adverse impacts of disease from the outset of development projects (23).…”

The minimum land area requiring conservation attention to safeguard biodiversity

“…Our estimate of the land area requiring effective biodiversity conservation must be considered the bare minimum needed, and will almost certainly expand as more data on the distributions of underrepresented species such as plants, invertebrates, and freshwater species becomes available for future analyses 47 . New KBAs will also continue to be identified for under-represented taxonomic groups, threatened or geographically-restricted ecosystems, and highly intact and irreplaceable ecosystems.…”