Biodiversity losses associated with global warming of 1.5 to 4°C above pre-industrial levels in six countries

We quantify the projected impacts of alternative levels of global warming upon the climatically determined geographic ranges of plants and vertebrates in six countries (China, Brazil, Egypt, Ethiopia, Ghana and India), accounting for uncertainties in regional climate projection. We quantify in a spatially explicit fashion the species richness remaining or lost, allowing the identification of climate refugia which we define as areas where > 75% ]of the species currently present remain in a world with a particular level of global warming above pre-industrial levels. In all countries and in both taxa, species richness declines with warming, as does the proportion of each country remaining a climate refugium for plants or vertebrates. In percentage terms, refugia loss relative to a 1961–1990 baseline period is greatest in India and Brazil, and least in Ghana and Ethiopia for the same level of warming, and is greater for plants than for vertebrates. Taking account of present land uses (i.e. area still considered natural), and using species richness of plants as a proxy to indicate biodiversity more generally, the proportion of land acting as climate refugia for biodiversity in five of the countries variously declines from 54–75% of a country in the 1961–1990 baseline period to 20–64% for 1.5 °C global warming, 11–53% for 2 °C, 3–33% for 3 °C and 2–24% for 4 °C warming. In Ethiopia, India, Brazil and China, climate refugia decline rapidly with warming while in Ghana and China some refugia persist even with 3–4 °C of warming. Only small percentages of Brazil, India and China are both climate refugia and lie within protected areas; hence, an expansion of the protected area networks in these countries would be required to deliver climate resilient biodiversity conservation. These percentages are larger in Ethiopia and Ghana and, in some areas of Ghana, the only remaining refugia are in protected areas, the remaining landscape converted to other uses

Investigating the potential impact of 1.5, 2 and 3 °C global warming levels on crop suitability and planting season over West Africa

West African rainfed agriculture is highly vulnerable to climate variability and change. Global warming is projected to result in higher regional warming and have a strong impact on agriculture. This study specifically examines the impact of global warming levels (GWLs) of 1.5°, 2° and 3 °C relative to 1971–2000 on crop suitability over West Africa. We used 10 Coupled Model Intercomparison Project Phase5 Global Climate Models (CMIP5 GCMs) downscaled by Coordinated Regional Downscaling Experiment (CORDEX) Rossby Centre’s regional Atmospheric model version 4, RCA4, to drive Ecocrop, a crop suitability model, for pearl millet, cassava, groundnut, cowpea, maize and plantain. The results show Ecocrop simulated crop suitability spatial representation with higher suitability, observed to the south of latitude 14°N and lower suitability to its north for 1971–2000 for all crops except for plantain (12°N). The model also simulates the best three planting months within the growing season from September-August over the past climate. Projected changes in crop suitability under the three GWLs 1.5–3.0 °C suggest a spatial suitability expansion for legume and cereal crops, notably in the central southern Sahel zone; root and tuber and plantain in the central Guinea-Savanna zone. In contrast, projected decreases in the crop suitability index value are predicted to the south of 14°N for cereals, root and tuber crops; nevertheless, the areas remain suitable for the crops. A delay of between 1-3 months is projected over the region during the planting month under the three GWLs for legumes, pearl millet and plantain. A two month delay in planting is projected in the south, notably over the Guinea and central Savanna zone with earlier planting of about three months in the Savanna-Sahel zones. The effect of GWL2.0 and GWL3.0 warming in comparison to GWL1.5 °C are more dramatic on cereals and root and tuber crops, especially cassava. All the projected changes in simulated crop suitability in response to climatic variables are statistically significant at 99% confidence level. There is also an increasing trend in the projected crop suitability change across the three warming except for cowpea. This study has implications for improving the resilience of crop production to climate changes, and more broadly, to food security in West Africa

Two sets of bias-corrected regional UK Climate Projections 2018 (UKCP18) of temperature, precipitation and potential evapotranspiration for Great Britain

The United Kingdom Climate Projections 2018 (UKCP18) regional climate model (RCM) 12 km regional perturbed physics ensemble (UKCP18-RCM-PPE) is one of the three strands of the latest set of UK national climate projections produced by the UK Met Office. It has been widely adopted in climate impact assessment. In this study, we report biases in the raw UKCP18-RCM simulations that are significant and are likely to deteriorate impact assessments if they are not adjusted. Two methods were used to bias-correct UKCP18-RCM: non-parametric quantile mapping using empirical quantiles and a variant developed for the third phase of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) designed to preserve the climate change signal. Specifically, daily temperature and precipitation simulations for 1981 to 2080 were adjusted for the 12 ensemble members. Potential evapotranspiration was also estimated over the same period using the Penman-Monteith formulation and then bias-corrected using the latter method. Both methods successfully corrected biases in a range of daily temperature, precipitation and potential evapotranspiration metrics, and reduced biases in multi-day precipitation metrics to a lesser degree. An exploratory analysis of the projected future changes confirms the expectation of wetter, warmer winters and hotter, drier summers, and shows uneven changes in different parts of the distributions of both temperature and precipitation. Both bias-correction methods preserved the climate change signal almost equally well, as well as the spread among the projected changes. The change factor method was used as a benchmark for precipitation, and we show that it fails to capture changes in a range of variables, making it inadequate for most impact assessments. By comparing the differences between the two bias-correction methods and within the 12 ensemble members, we show that the uncertainty in future precipitation and temperature changes stemming from the climate model parameterisation far outweighs the uncertainty introduced by selecting one of these two bias-correction methods. We conclude by providing guidance on the use of the bias-corrected data sets. The data sets bias adjusted with ISIMIP3BA are publicly available in the following repositories: https://doi.org/10.5281/zenodo.6337381 for precipitation and temperature (Reyniers et al., 2022a) and https://doi.org/10.5281/zenodo.6320707 for potential evapotranspiration (Reyniers et al., 2022b) . The datasets bias-corrected using the quantile mapping method are available at https://doi.org/10.5281/zenodo.8223024 (Zha et al., 2023)

Assessing the potential risks of climate change on the natural capital of six countries resulting from global warming of 1.5 to 4 °C above pre‑industrial levels

We present the results from a new framework providing an assessment of how climate change risks to natural capital accrue with warming of 1.5–4 °C in six countries (China, Brazil, Egypt, Ethiopia, Ghana, and India). Unlike typical biodiversity and climate change studies, this assessment also considers landcover and population changes across a range of 17 ecosystem services. The potential impacts of climate change (alone) on natural capital at 1.5 °C is greatest in Brazil and least in Ghana. However, when population and landcover change are included, areas projected to be at high natural capital risk begin to accrue by 1.5 °C in all countries. By 2 °C, Ethiopia and Ghana show increasing areas at high risk, even though they are at low risk owing to climate alone. Thus, current impacts to biodiversity and ecosystem services and changes in potential demand coupled with warming exceed changes projected by climate alone. However, this also indicates that there is adaptation potential, especially with warming of<2 °C, to reduce risk through restoring habitat. At lower levels of warming, targeted restoration of marginal agricultural habitats would increase the bank of natural capital for use by people and provide support for remaining agricultural lands. By 3 °C, the adaptation potential from restoration is substantially less:<1% in Brazil, India and Egypt; 7–8% in China and Ethiopia; but still 26% in Ghana. This indicates that restoration as an adaptation option for biodiversity, and thus, natural capital, rapidly decreases with increasing temperatures. By 2100, factoring in population change (SSP2), current ecological footprint, and current landcover, even with only 1.5 °C warming, large parts of Brazil, eastern China, most of Egypt, much of Ethiopia, southwestern Ghana (except for protected areas), and most of India are at high to extreme natural capital risk with an adaptation deficit potentially equating to a soft adaptation limit

Quantifying future changes of flood hazards within the Broadland catchment in the UK

Flooding represents the greatest natural threat to the UK, presenting severe risk to populations along coastlines and floodplains through extreme tidal surge and hydrometeorological events. Climate change is projected to significantly elevate flood risk through increased severity and frequency of occurrences, which will be exacerbated by external drivers of risk such as property development and population growth throughout floodplains. This investigation explores the entire flood hazard modelling chain, utilising the nonparametric bias correction of UKCP18 regional climate projections, the distributed HBV-TYN hydrological model and HEC-RAS hydraulic model to assess future manifestation of flood hazard within the Broadland Catchment, UK. When assessing the independent impact of extreme river discharge and storm surge events as well as the impact of a compound event of the two along a high emission scenario, exponential increases in hazard extent over time were observed. The flood extent increases from 197 km2 in 1990 to 200 km2 in 2030, and 208 km2 in 2070. In parallel, exponential population exposure increases were found from 13,917 (1990) to 14,088 (2030) to 18,785 (2070). This methodology could see integration into policy-based flood risk management by use of the developed hazard modelling tool for future planning and suitability of existing infrastructure at a catchment scale

Quantification of meteorological drought risks between 1.5 °C and 4 °C of global warming in six countries

We quantify the projected impacts of alternative levels of global warming upon the probability and length of severe drought in six countries (China, Brazil, Egypt, Ethiopia, Ghana and India). This includes an examination of different land cover classes, and a calculation of the proportion of population in 2100 (SSP2) at exposed to severe drought lasting longer than one year. Current pledges for climate change mitigation, which are projected to still result in global warming levels of 3 °C or more, would impact all of the countries in this study. For example, with 3 °C warming, more than 50% of the agricultural area in each country is projected to be exposed to severe droughts of longer than one year in a 30-year period. Using standard population projections, it is estimated that 80%-100% of the population in Brazil, China, Egypt, Ethiopia and Ghana (and nearly 50% of the population of India) are projected to be exposed to a severe drought lasting one year or longer in a 30-year period. In contrast, we find that meeting the long-term temperature goal of the Paris Agreement, that is limiting warming to 1.5 °C above pre-industrial levels, is projected to greatly benefit all of the countries in this study, greatly reducing exposure to severe drought for large percentages of the population and in all major land cover classes, with Egypt potentially benefiting the most

Quantifying risks avoided by limiting global warming to 1.5 or 2 °C above pre-industrial levels

The Paris Agreement aims to constrain global warming to ‘well below 2 °C’ and to ‘pursue efforts’ to limit it to 1.5 °C above pre-industrial levels. We quantify global and regional risk-related metrics associated with these levels of warming that capture climate change–related changes in exposure to water scarcity and heat stress, vector-borne disease, coastal and fluvial flooding and projected impacts on agriculture and the economy, allowing for uncertainties in regional climate projection. Risk-related metrics associated with 2 °C warming, depending on sector, are reduced by 10–44% globally if warming is further reduced to 1.5 °C. Comparing with a baseline in which warming of 3.66 °C occurs by 2100, constraining warming to 1.5 °C reduces these risk indicators globally by 32–85%, and constraining warming to 2 °C reduces them by 26–74%. In percentage terms, avoided risk is highest for fluvial flooding, drought, and heat stress, but in absolute terms risk reduction is greatest for drought. Although water stress decreases in some regions, it is often accompanied by additional exposure to flooding. The magnitude of the percentage of damage avoided is similar to that calculated for avoided global economic risk associated with these same climate change scenarios. We also identify West Africa, India and North America as hotspots of climate change risk in the future

Report on the observed climate, projected climate, and projected biodiversity changes for Bwindi Impenetrable National Park, Uganda under differing levels of warming

Critically important for the endangered Mountain Gorilla (containing nearly half of the population), Bwindi Impenetrable National Park, Uganda, is among the top 21% of all non-marine protected areas, globally. As a park with varying topography, the higher elevations are more resilient to climate change, however most of the southern portions of the park are resilient to 4°C warming. As such, business as usual conservation, taking into account changes in the likelihood of extreme events, will be adequate except in the most northern parts of the park. Averaged over the entire area, with 4°C warming (global, above pre-industrial), the area is projected to remain climatically suitable for 66.8% of its terrestrial biodiversity (fungi, plants, invertebrates, and vertebrates), with 40.9% of its area remaining an overall refugia (remaining climatically suitable for >75% of the species) for biodiversity. If warming levels were held to 2°C, 85.8% of the area would remain a climatic refugia and the area would remain climatically suitable for 88.4% of its terrestrial biodiversity. Between 1961-1990 and 1991-2020 the average monthly temperature has increased by 0.5° – 0.8°C. With warming levels of 1.5°C the new average monthly temperature is equivalent to that only seen 1 in 20 years in 1961-1990 for all months. Seven months have seen declines in precipitation (especially April), and the rest wetter, especially January and October. Models project that April, May, July and September will become drier and the rest increase or not change. The number of months with severe drought has more than doubled between 1961-1990 and 1986-2015. Biodiversity adaptation options generally only allow for business-as-usual conservation to 4.0°C in the southern part of the park, taking into account changes in extreme events (especially heat and severe drought). At temperatures above 3.0°C the northern parts of the park will require increasing levels of adaptation. Mammals tend to fare somewhat better than biodiversity as a whole. The human population around the park is projected to increase substantially and this will likely have impacts on the park as a whole and needs to be carefully monitored

Report on the observed climate, projected climate, and projected biodiversity changes for Big Bend National Park, Texas under differing levels of warming

Big Bend National Park, Texas, is among the top 26% of all non-marine protected areas, globally. Big Bend is projected to be largely resilient to climate change to 2°C warming. As such, business as usual conservation, taking into account changes in the likelihood of extreme events (heat and drought), should largely be adequate. Beyond that, only the higher elevations are expected to remain resilient with the lower elevations requiring increasing adaptation effort. Individual species will be expected to shift upward in elevation, if they are able and those at the very top of the mountains may be extirpated. Averaged over the entire area, with 4°C warming (global, above pre-industrial), the area is projected to remain climatically suitable for 65.1% of its terrestrial biodiversity (fungi, plants, invertebrates, and vertebrates), with only 4% of its area remaining an overall refugia (remaining climatically suitable for >75% of the species) for biodiversity. If warming levels were held to 2°C, 54.4% of the area would remain a climatic refugia and the area would remain climatically suitable for 81.7% of its terrestrial biodiversity. Between 1961-1990 and 1991-2020 the average monthly temperature has increased by 0.4° – 1.4°C (February). With warming levels of 2°C the new average monthly temperature is equivalent to that currently seen 1 in 3 years in 1961-1990 for all months except May and June (new average equal to that seen in 1 in 20 years). Eight months have seen decreases in precipitation (especially September), and the rest wetter, especially July. Models project that all months except July and August will become drier. The number of months with severe drought has more than quadrupled between 1961-1990 and 1986-2015. With 2°C warming, more than half of the months in a 30-year period are projected to be in severe drought, with severe drought lengths of more than three years possible. Biodiversity adaptation options generally only allow for business-as-usual conservation to 2.0°C, but this would only be possible if changes in extreme events (especially summer heat and severe drought) were taken into consideration. Even with warming of 2°C and less, water may become increasingly scarce so water holes or guzzlers may be required to maintain existing biodiversity. With warming above 2°C adaptation will become increasingly difficult as lengths of severe drought increase. Only the highest elevations in the park would be able to potentially get by with business-as-usual conservation

Report on the observed climate, projected climate, and projected biodiversity changes for Volcanoes National Park, Rwanda under differing levels of warming

Critically important for the endangered Mountain Gorilla, Volcanoes National Park, Rwanda, is among the top 1% of all non-marine protected areas, globally. Volcanoes is projected to be largely resilient to climate change, even with 4°C warming. As such, business as usual conservation, taking into account changes in the likelihood of extreme events (heat and drought), should largely be adequate. Averaged over the entire area, with 4°C warming (global, above pre-industrial), the area is projected to remain climatically suitable for 92.3% of its terrestrial biodiversity (fungi, plants, invertebrates, and vertebrates), with 97.7% of its area remaining an overall refugia (remaining climatically suitable for >75% of the species) for biodiversity. If warming levels were held to 2°C, 100% of the area would remain a climatic refugia and the area would remain climatically suitable for 98.4% of its terrestrial biodiversity. Between 1961-1990 and 1991-2020 the average monthly temperature has increased by 0.4° – 0.8°C. With warming levels of 1.5°C the new average monthly temperature is equivalent to that only seen 1 in 20 years in 1961-1990 for all months. Eight months have seen declines in precipitation (especially April), and the rest wetter, especially January and October. Models project that April - July and September will become drier and the rest increase. The number of months with severe drought nearly doubled between 1961-1990 and 1986-2015. Biodiversity adaptation options generally only allow for business-as-usual conservation to 4.0°C, taking into account changes in extreme events (especially heat and severe drought). The human population around the park is projected to increase substantially and this could impact on the park needing carefully monitoring. Between 1992 and 2020 areas in the park have already been converted into agricultural land