Stephen Polasky

Globally, cities account for 78% of energy consumption and 70~75% of greenhouse gas emissions. Using spatially explicit data on urban vegetation, water bodies, and buildings, combined with extensive daily observations of air temperature and electricity consumption for the subtropical megacity of Shenzhen, China, this study shows that urban nature contributes to urban cooling, reducing energy consumption and associated greenhouse gas emissions. We found that green and blue spaces in the city’s built-up area had a pronounced influence on air temperature, ranging from a cooling effect of 1.27 °C to a warming effect of 0.29 °C, with the cooling effect being dominant over the course of a year. The cooling effect was greatest at moderate temperatures (~20 °C) and was lower on hotter days. We identified a temperature threshold of 16 to 18 °C above which urban nature produces measurable reductions in cooling energy demand. We found that residential electricity consumption was more temperature-sensitive than nonresidential electricity consumption. For the study year of 2021, the net electricity savings from urban nature was 1.5 billion kWh. This reduction in energy consumption translated to almost one million tons of avoided CO ₂ emissions, which was 4.65-times the sequestration capacity of the city’s terrestrial vegetation and equivalent to the annual emissions of over 223 thousand people using global average annual per capita carbon emissions.

The Tibetan Plateau, the Earth’s highest and largest plateau, has a harsh environment for agriculture, and is a global biodiversity hotspot, raising the challenge of simultaneously satisfying food production and conservation goals. Currently, agriculture involves crop production on steep slopes and overgrazing, which threatens future productivity. The Tibetan Plateau is also undergoing climate change. We evaluate food production from 1990 to 2020 and use these results to model future trends and risks to food production on the Tibetan Plateau. We assess the feasibility of achieving both food production and conservation goals simultaneously under climate change scenarios. Food production increased 32.33% over three decades, providing 2,892.98 kcal d ⁻¹ cap ⁻¹ , more than enough to satisfy food self-sufficiency. Under climate change, the Tibetan Plateau will become warmer and wetter under Shared Socioeconomic Pathways (SSPs) SSP126, SSP245, and SSP585, which combined with agricultural advances (e.g., improved mechanization and irrigation), will likely result in increased yields even with a 10% reduction in cropland area—greater than the total area of all steeply sloping cropland, thereby allowing retirement of steeply sloping cropland and livestock reductions while still meeting food production goals. Meanwhile, key ecosystem services, including carbon sequestration, water retention, and habitat quality, are also projected to improve substantially. Nonetheless, the increasing frequency and severity of extreme weather events are expected to reduce food production, undermine current dietary requirements and may threaten the minimum nutritional intake required for humans.

National governments and multilateral institutions face difficult challenges reconciling biodiversity, climate, and economic development goals. We integrated spatial biophysical and economic data with optimization methods to develop sustainable landscape efficiency frontiers that show maximally feasible combinations of biodiversity conservation, land-based climate mitigation, and net economic value from agricultural crops, livestock, and forestry production. We applied this approach in 146 countries and found large potential gains in biodiversity, climate, and economic development from improved land use and land management. Summing national-level results shows the potential to increase climate mitigation by more than 200 billion metric tons of CO ₂ equivalents (>20% increase) or net economic value by more than US$350 billion (>80% increase), without loss in other objectives.

As one of the main causes of habitat loss, agricultural cropland expansion is a major threat to biodiversity. We analyze past and anticipated future trends in population, per capita crop demand, and crop yield to estimate agricultural cropland requirements globally by 2050 and 2100, assuming moderate levels of climate change. According to a model of “business as usual,” higher-income countries would be expected to show little or no net growth in cropland by the end of the century whereas cropland area could nearly double in lower-income countries. We consider two strategies to reduce global cropland expansion: decreasing per capita crop demand in higher-income countries by eating healthier diets, reducing food waste, and reducing biofuel production, and accelerating economic development in lower-income countries. Economic development in lower-income countries could reduce future cropland requirements via slower population growth, improved crop yield, and higher volumes of global crop trade, which could more than offset rising per capita crop demand. These impacts would far exceed reductions in cropland requirements from decreased crop demand in higher-income countries. Further, by combining accelerated economic development in lower-income countries with reduced crop demand in higher-income countries in tandem with reduced trade friction, global cropland requirements could shrink dramatically by the year 2100. Although economic growth is often considered to work in opposition to environmental conservation, accelerating economic development in lower-income countries would not only help alleviate poverty but could also confer benefits for biodiversity and global climate change.

Fuelwood remains a major traditional energy source for more than 264 million households worldwide. However, its global impacts on sustainability are poorly quantified. Here, we develop an integrated framework combining energetic, economic, and environmental perspectives to evaluate the livelihood, economic, carbon emission, and biodiversity impacts of global fuelwood consumption from 2000 to 2021 and to project outcomes under alternative energy and management scenarios for 2030 and 2050. We find that global fuelwood consumption reached 1.9 billion m³ in 2021 (2.5% of primary energy use). The economic value was $190 billion, accounting for 0.2% of global GDP but up to 6.7% in low-income countries. Fuelwood use by all income levels together generated 1.1-1.7 Gt CO₂ emissions and significantly undermined global biodiversity integrity. Counterfactual simulations show that substituting 90% of unsustainably harvested fuelwood with renewable energy could reduce global primary energy emissions by 3.2-4.4% and increase biodiversity integrity by 0.3%. By 2050, policy interventions would markedly improve carbon and biodiversity outcomes. Forest certification reduces emissions by up to 99.7, 98.4, and 74.0% in high-, upper-middle-, and lower-middle-income countries, respectively. In low-income countries, clean energy substitution reduces emissions by 61.3%, while LPG and clean energy scenarios increase biodiversity integrity by up to 65.6% and further improve outcomes in higher-income groups. These findings underscore the importance of systemic approaches that explicitly account for trade-offs and synergies among energy access, livelihoods, carbon mitigation, and biodiversity conservation in fuelwood management.

Corporate sustainability reporting currently fails to provide the information needed for companies, their investors and society to address mounting environmental risks because predominant reporting requirements focus heavily on firm-level risks, neglecting cumulative impacts on climate and nature. Recently, sustainability reporting has also been critiqued for the administrative burden it places on companies. Corporate reporting may seem far removed from sustainability science but is, in fact, a critical lever in directing corporate practice. A golden opportunity therefore exists for sustainability science to simultaneously help reduce, refine and improve sustainability reporting by identifying the most prioritized mandatory environmental disclosures and support the development of an open-access disclosure repository. This would radically improve the ability of investors, regulators, and public agencies to appraise environmental pressures, improve corporate accountability, and mitigate growing systemic risks. Treating environmental data with the rigor granted to financial data is fundamental to align capital with sustainability objectives.

Remotely sensed Earth science information (ESI) has become increasingly central to addressing global challenges, yet its societal value, i.e., the difference ESI makes in real-world decisions and outcomes, is rarely quantified. In this study, we systematically map peer-reviewed literature that explicitly assesses the societal value of ESI across instrumental, intrinsic, and relational value types, and the diversity of approaches used to assess those values. Drawing from 13,823 publications across Scopus, Web of Science, and a curated library of ESI valuation studies, we identify 171 studies that applied ESI in a decision context and used a valuation method to compare outcomes with and without ESI. The majority of these studies employed decision analysis methods (e.g., Value of Information, Cost–Benefit Analysis), focusing primarily on quantitative instrumental values (e.g., profit, crop yield, lives saved), particularly in agricultural contexts. A smaller set of studies applied preference elicitation methods (e.g., stated preference, surveys, interviews, focus groups) to capture qualitative benefits and relational values including quality of life improvements, empowerment, and procedural justice. Many excluded studies demonstrated scientific value of ESI but did not explicitly translate that into societal value, revealing the need for a more systematic approach to ESI valuation. By promoting a more inclusive, interdisciplinary, and flexible portfolio of valuation methods, we aim to expand our understanding of the societal benefits of ESI to help guide investment in future missions, enhance public support, and ensure that science and policy goals are well aligned.