The lockdown response to coronavirus disease 2019 (COVID-19) has caused an unprecedented reduction in global economic and transport activity. We test the hypothesis that this reduced tropospheric ground-level air pollution concentrations, using satellite data a network of >10,000 quality stations. After accounting for effects meteorological variability, we find declines population-weighted concentration nitrogen dioxide (NO 2 : 60% with 95% CI 48 72%), fine particulate matter (PM 2.5 31%;...

The global response to the COVID-19 pandemic has brought with it significant changes human mobility patterns and working environments. We aimed explore how social distancing measures affected recreational use of urban green space during partial lockdown in Oslo, Norway. Mobile tracking data from thousands recreationists were used analyze high resolution spatio-temporal activity. estimated that outdoor activity increased by 291% relative a 3 yr average for same days. This increase was...

While global deforestation induced by human land use has been quantified, the drivers and extent of simultaneous woody plant encroachment (WPE) into open areas are only regionally known. WPE important consequences for ecosystem functioning, carbon balances economies. Here we report, using high-resolution satellite imagery, that vegetation cover over sub-Saharan Africa increased 8% past three decades a diversity drivers, other than CO2, were able to explain 78% spatial variation in this...

Urban green infrastructure provides ecosystem services that are essential to human wellbeing. A dearth of national-scale assessments in the Global South has precluded ability explore how political regimes, such as forced racial segregation Africa during and after Apartheid, have influenced extent access over time. We investigate whether there disparities distributions across race income geographies urban Africa. Using open-source satellite imagery geographic information, along with national...

In Oslo, as elsewhere, the COVID-19 outbreak and following lockdown measures during spring 2020 led to increased use of urban green infrastructure. Whether this has more durable changes in recreation patterns remains an open question. We used mobile tracking data from 53,000 STRAVA users explore longevity increases recreational activity. compared activity levels relative a weather benchmark (i.e. baseline), defined one would have expected given time year prevailing conditions. Recreational...

Satellites overestimate urban heat islands.

The European Space Agency’s Sentinel satellites have laid the foundation for global land use cover (LULC) mapping with unprecedented detail at 10 m resolution. We present a cross-comparison and accuracy assessment of Google’s Dynamic World (DW), ESA’s Cover (WC) Esri’s Land (Esri) products first time in order to inform adoption application these maps going forward. For year 2020, three LULC show strong spatial correspondence (i.e., near-equal area estimates) water, built area, trees crop...

The impacts of climate change such as extreme heat waves are exacerbated in cities where most the world's population live. Quantifying urbanization on ambient air temperatures (Tair) has relevance for human health risk, building energy use efficiency, vector-borne disease control and urban biodiversity. Remote sensing been focused land surface temperature (LST) due to a scarcity data Tair which is usually interpolated at 1 km resolution. We assessed efficacy mapping hyperlocal (spatial...

Abstract Surface temperature is often used to examine heat exposure in multi‐city studies and for informing urban mitigation efforts due scarcity of air measurements. Cities also have lower relative humidity, traditionally not accounted large‐scale observational risk assessments. Here, using crowdsourced measurements from over 40,000 weather stations ≈600 clusters Europe, we show the moderating effect this urbanization‐induced humidity reduction on outdoor stress during 2019 heatwave. We...

The assumption that vegetation improves air quality is prevalent in scientific, popular, and political discourse. However, experimental modeling studies show the effect of green space on pollutant concentrations urban settings highly variable context specific. We revisited link between using satellite-derived changes from 2,615 established monitoring stations over Europe United States. Between 2010 2019, recorded declines ambient NO 2 , (particulate matter) PM 10 2.5 (average −3.14% y −1 ),...

The predicted extreme temperatures of global warming are magnified in cities due to the urban heat island effect. Even if target for average temperature increase Paris Climate Agreement is met, during hottest month a northern city like Oslo rise by over 5 °C 2050. We hypothesised that heat-related diagnoses heat-sensitive citizens (75+) correlated monthly air temperatures, and green infrastructure such as tree canopy cover reduces land surface thus health risk from exposure. Monthly were...

Abstract The lockdown response to COVID-19 has caused an unprecedented reduction in global economic activity. We test the hypothesis that this reduced tropospheric and ground-level air pollution concentrations using satellite data a network of >10,000 quality stations. After accounting for effects meteorological variability, we find remarkable declines nitrogen dioxide (NO 2 : −29 % with 95% confidence interval −44% −13%), ozone (O 3 −11%; −20% −2%) fine particulate matter (PM 2.5 −9%;...

The lockdown response to COVID-19 has resulted in an unprecedented reduction global economic activity and associated air pollutant levels, especially from a decline land transportation. We utilized network of >10,000 quality stations distributed over 34 countries during dates up until 15 May 2020 obtain related anomalies for nitrogen dioxide, ozone particulate matter smaller than 2.5 μm diameter (PM2.5). Pollutant were short-term health outcomes using empirical exposure-response functions....

Widely used European land cover maps such as CORINE are produced at medium spatial resolutions (100 m) and rely on diverse data with complex workflows requiring significant institutional capacity. We present a high resolution (10 map (ELC10) of Europe based satellite-driven machine learning workflow that is annually updatable. A Random Forest classification model was trained 70K ground-truth points from the LUCAS (Land Use/Cover Area frame Survey) dataset. Within Google Earth Engine cloud...

Spatial multi-criteria decision analysis (MCDA) is increasingly being used to inform urban green infrastructure planning. We explore the use of modern cloud computing technologies (Google Earth Engine) facilitate public access spatial MCDA ecosystem services from infrastructure. Using prioritization roof retrofitting in Oslo, Norway, as a case study, we present web application that generalizable tool for engaging stakeholders planning restoration and nature-based solutions. In our...

Estimation and monitoring of soil organic carbon (SOC) stocks is important for maintaining productivity meeting climate change mitigation targets. Current global SOC maps do not provide enough detail landscape-scale decision making, allow tracking sequestration or loss over time. Using an optical satellite-driven machine learning workflow, we mapped (topsoil; 0 to 30 cm) under natural vegetation (86% land area) South Africa at m spatial resolution between 1984 2019. We estimate a total...

Poorer citizens are often more exposed to environmental hazards due spatial inequalities in the distribution of urban blue-green space. Few cities have managed prevent and social inequality despite sustainable development strategies like compact city planning. We explore whether injustice exists a where one would least expect find it: with abundant nature, an affluent population governed by left leaning democratic council, aggressive densification strategy; Oslo, Norway. Green space was...

Assumptions about the link between green space and crime mitigation are informed by literature that overwhelmingly originates in Global North. Little is known association spaces South. We utilized 10 years of precinct-level statistics (n = 1152) over South Africa, a global hotspot, to test hypothesis associated with reduced rates. found that, after controlling for number socio-demographic confounders (unemployment, income, age, education, land use population density), every 1% increase total...

Recreational activity is the single most valuable ecosystem service in many developed countries with a range of benefits for public health. Crowdsourced recreational data increasingly being adopted management and monitoring urban landscapes, however inherent biases make it difficult to generalize patterns total population. We used in-situ observations questionnaires quantify accuracy Strava - widely outdoor app – Oslo, Norway. The precision which captured spatial (R2 = 0.9) temporal...

Abstract Machine learning is increasingly applied to Earth Observation (EO) data obtain datasets that contribute towards international accords. However, these contain inherent uncertainty needs be quantified reliably avoid negative consequences. In response the increased need report uncertainty, we bring attention promise of conformal prediction within domain EO. Unlike previous quantification methods, offers statistically valid regions while concurrently supporting any machine model and...

Abstract Accurately capturing the impact of urban trees on temperature can help optimize heat mitigation strategies. Recently, there has been widespread use remotely sensed land surface ( T s ) to quantify cooling efficiency (CE) trees. However, reflects emitted radiation from an object seen point view thermal sensor, which is not a good proxy for air perceived by humans. The extent CEs derived reflect true experiences residents debatable. Therefore, this study systematically compared -based...

Monitoring vegetation change is important because the nature, extent and rate of in key measures, such as plant biomass, cover species composition, provides critical insight into broader environmental land use drivers leads to development appropriate policy. We used Landsat data between 1984 2018 produce a map Enhanced Vegetation Index (EVI) over South Africa at 30 m resolution an interactive web application make analysis both globally applicable locally meaningful. found increase EVI 0.37 ±...

The global response to the COVID-19 pandemic has brought with it significant changes human mobility patterns. We aimed explore how social distancing measures affected recreational use of urban green space during partial lockdown in Oslo, Norway. Mobile tracking data from thousands recreationists were used analyze high resolution spatio-temporal activity. estimated that outdoor activity increased by 291% relative a 3-yr average for same days. This increase was significantly greater than...

Improvements in high-resolution satellite remote sensing and computational advancements have sped up the development of global datasets that delineate urban land, crucial for understanding climate risks our increasingly urbanizing world. Here, we analyze land cover patterns across spatiotemporal scales from several such current-generation products. While all show a rapidly world, with nearly tripling between 1985 2015, there are substantial discrepancies area estimates among products...