Climate change hotspots mapping: what have we learned?

In the past 5 years there has been a proliferation of efforts to map climate change “hotspots” — regions that are particularly vulnerable to current or future climate impacts, and where human security may be at risk. While some are academic exercises, many are produced with the goal of drawing policy maker attention to regions that are particularly susceptible to climate impacts, either to mitigate the risk of humanitarian crises or conflicts or to target adaptation assistance. Hotspots mapping efforts address a range of issues and sectors such as vulnerable populations, humanitarian crises, conflict, agriculture and food security, and water resources. This paper offers a timely assessment of the strengths and weaknesses of current hotspots mapping approaches with the goal of improving future efforts. It also highlights regions that are anticipated, based on combinations of high exposure, high sensitivity and low adaptive capacity, to suffer significant impacts from climate change

Social vulnerability to floods in two coastal megacities: New York City and Mumbai

In this paper we assess differential exposure to flooding in two coastal megacities, New York and Mumbai, both of which suffered major flood-related disasters in the past decade. Specifically, we examine whether the most exposed populations are also the most socially vulnerable. First, we developed Social Vulnerability Indices (SoVIs) for each city with census data. We then overlaid the SoVI scores onto flood extent maps for Hurricane Sandy (New York, October 2012) and the Mumbai flash floods (July 2005), as well as for the evacuation zones for New York, to examine patterns of differential exposure. Our results suggest a degree of differential exposure in New York, especially in the highest flood risk areas, and provide fairly clear evidence for differential exposure in Mumbai. However, differences in the input resolution and confidence in the datasets for Mumbai make the results more uncertain. The paper concludes with a discussion of the policy implications and the data needs for urban spatial vulnerability assessments

Landsat-Derived Estimates of Mangrove Extents in the Sierra Leone Coastal Landscape Complex during 1990–2016

This study provides the first assessment of decadal changes in mangrove extents in Sierra Leone. While significant advances have been made in mangrove mapping using remote sensing, no study has documented long-term changes in mangrove extents in Sierra Leone—one of the most vulnerable countries in West Africa. Such understanding is critical for devising regional management strategies that can support local livelihoods. We utilize multi-date Landsat data and cloud computational techniques to quantify spatiotemporal changes in land cover, with focus on mangrove ecosystems, for 1990–2016 along the coast of Sierra Leone. We specifically focus on four estuaries—Scarcies, Sierra Leone, Yawri Bay, and Sherbro. We relied on the k-means approach for an unsupervised classification, and validated the classified map from 2016 using ground truth data collected from Sentinel-2 and high-resolution images and during field research (accuracy: 95%). Our findings indicate that the Scarcies river estuary witnessed the greatest mangrove loss since 1990 (45%), while the Sierra Leone river estuary experienced mangrove gain over the last 26 years (22%). Overall, the Sierra Leone coast lost 25% of its mangroves between 1990 and 2016, with the lowest coverage in 2000, during the period of civil war (1991–2002). However, natural mangrove dynamics, as supported by field observations, indicate the potential for regeneration and sustainability under carefully constructed management strategies

Temperature and humidity based projections of a rapid rise in global heat stress exposure during the 21st century

As a result of global increases in both temperature and specific humidity, heat stress is projected to intensify throughout the 21st century. Some of the regions most susceptible to dangerous heat and humidity combinations are also among the most densely populated. Consequently, there is the potential for widespread exposure to wet bulb temperatures that approach and in some cases exceed postulated theoretical limits of human tolerance by mid- to late-century. We project that by 2080 the relative frequency of present-day extreme wet bulb temperature events could rise by a factor of 100–250 (approximately double the frequency change projected for temperature alone) in the tropics and parts of the mid-latitudes, areas which are projected to contain approximately half the world's population. In addition, population exposure to wet bulb temperatures that exceed recent deadly heat waves may increase by a factor of five to ten, with 150–750 million person-days of exposure to wet bulb temperatures above those seen in today's most severe heat waves by 2070–2080. Under RCP 8.5, exposure to wet bulb temperatures above 35 °C—the theoretical limit for human tolerance—could exceed a million person-days per year by 2080. Limiting emissions to follow RCP 4.5 entirely eliminates exposure to that extreme threshold. Some of the most affected regions, especially Northeast India and coastal West Africa, currently have scarce cooling infrastructure, relatively low adaptive capacity, and rapidly growing populations. In the coming decades heat stress may prove to be one of the most widely experienced and directly dangerous aspects of climate change, posing a severe threat to human health, energy infrastructure, and outdoor activities ranging from agricultural production to military training

A Systematic Review of Coastal Vulnerability Mapping

Coastal areas worldwide represent an aggregation of population and assets of growing economic, geopolitical, and sociocultural significance, yet their functions are increasingly challenged by worsening coastal hazards. Vulnerability assessments have been recognized as one way we can better understand which geographic areas and segments of society are more susceptible to adverse impacts from different stressors or hazards. The aims of this paper are to evaluate the state of coastal vulnerability assessment mapping efforts and to identify opportunities for advancement and refinement that will lead to more cohesive, impactful, and policy-relevant coastal vulnerability studies. We conducted a systematic review of the literature that addresses physical and social vulnerability to coastal hazards and contains corresponding mapping products. The content was analyzed for the scale of analysis, location, disciplinary focus, conceptual framework, metrics used, methodological approach, data sources, mapping output, and policy relevance. Results showed that most Coastal Vulnerability Mapping Assessments (CVMAs) are conducted at the local level using a range of methodologies, often with limited inclusion of social considerations and limited discussion of policy relevance. Based on our analysis, we provide seven recommendations for the advancement of this field that would improve CVMAs’ methodological rigor, policy relevance, and alignment with other vulnerability assessment paradigms

A New Dataset Integrating Public Socioeconomic, Physical Risk, and Housing Data for Climate Justice Metrics: A Test-Case Study in Miami

Assessing the impact of climate change on vulnerable populations and the implications of such impacts is a critical step toward climate and environmental justice. In general, indices or metrics that aim at studying linkages between climatic environmental impacts and vulnerable populations lack housing information. Financially relevant real estate data (e.g., mortgages, evictions) alongside other socioeconomic and physical risk information can, however, provide a crucial lens to assess climate justice. In addition, standard socioeconomic and demographic variables aggregated at census units lack the granularity required to capture inequalities, especially in heterogeneous communities, so there is a need for publicly available, ready-to-use, digitized, and distributed datasets containing relevant inequality metrics using real estate and financial information. Also, studies focusing on damages and financial impacts of climate change often use commercial datasets, which must be acquired for hundreds of thousands of dollars, making the inclusion of such information prohibitive for advocacy groups, journalists, and other interested people. With this in mind, we integrated multiple publicly available datasets that include socioeconomic, climate risk scores, evictions, and housing variables at the census tract level over the United States to be used to investigate environmental justice themes. Our goal is that the dataset proposed here will allow for testing, assessing, and generating new analysis and metrics that can address inequalities and climate injustice. To demonstrate the potential of the new dataset, we report examples of application to the Miami area, where the recent increased risk of floods and extreme events has exposed socially vulnerable populations to the consequences of climate change

Climate Mobility and Development Cooperation

Development cooperation actors have been addressing climate change as a cross-cutting issue and investing in climate adaptation projects since the early 2000s. More recently, as concern has risen about the potential impacts of climate variability and change on human mobility, development cooperation actors have begun to design projects that intentionally address the drivers of migration, including climate impacts on livelihoods. However, to date, we know little about the development cooperation’s role and function in responding to climate related mobility and migration. As such, the main aim of this paper is to outline the policy frameworks and approaches shaping development cooperation actors’ engagement and to identify areas for further exploration and investment. First, we frame the concept of climate mobility and migration and discuss some applicable policy frameworks that govern the issue from various perspectives; secondly, we review the toolbox of approaches that development cooperation actors bring to climate mobility; and third, we discuss the implications of the current Covid-19 pandemic and identify avenues for the way forward. We conclude that ensuring safe and orderly mobility and the decent reception and long-term inclusion of migrants and displaced persons under conditions of more severe climate hazards, and in the context of rising nationalism and xenophobia, poses significant challenges. Integrated approaches across multiple policy sectors and levels of governance are needed. In addition to resources, development cooperation actors can bring data to help empower the most affected communities and regions and leverage their convening power to foster more coordinated approaches within and across countries

Curating Big Data on Population and Settlements to Monitor the Sustainable Development Goals (SDGs)

Spatial data describing population distribution and settlement patterns can be used, either alone or in conjunction with other data products and services such as Earth observations and in situ data, to assess progress on implementing the SDGs and to identify where additional efforts could benefit specific groups of people—especially those who might otherwise be left behind. Spatial population data are critical to the development and use of many SDG indicators, especially those based on per capita rates or computed separately for urban versus rural areas. However, to effectively utilize population and settlement data over time in the context of SDG monitoring and decision making, the data need to be curated, effectively managed throughout the data lifecycle, and persistently accessible in an open manner. Furthermore, in light of the interconnectedness of the SDGs, curation of population and settlement data needs to support cross-disciplinary and cross-sector use and reuse, to support consistency in monitoring, targeting, and decision making within and across countries, sectors, and time periods. Supporting long-term transdisciplinary use of population and settlement data, ensuring that these data are Findable, Accessible, Interoperable, and Reusable (FAIR), clearly communicating their open access status, and describing their quality are essential capabilities that enable diverse users to effectively, efficiently, and transparently apply these data to their pressing challenges. Examples of population and settlement data for monitoring the SDGs are described along with approaches for curating, managing, and disseminating these data as open data for long-term use by diverse user communities

What is the role for conservation organizations in poverty alleviation in the world’s wild places?

In this paper we provide an empirically-based way to address the general question of the broad-scale spatial relationship between poverty occurrence and areas of interest to those seeking conservation of large wild areas. We address the question of the spatial relationship between poor people and areas less impacted by human activity by asking three questions about the global spatial relationship between poor people and ecological intactness and how it varies by major biome and geographical region. We use infant mortality rate as a proxy for poverty and the Human Footprint as a proxy for ecological intactness, comparing global terrestrial maps of both. The analysis shows that the vast majority of the world’s poor people live in extremely urban and very transformed (peri transformed) areas. Only a small percentage of the world’s most poor are found in areas that are somewhat or extremely wild: about 0.25% of the world’s population. This fact has implications for the calls being made for conservation organizations to undertake poverty alleviation, suggesting that at a global scale those groups with interest in conserving wild areas would be able to contribute little to globally significant poverty alleviation efforts. However, these conservation groups are well positioned to develop new partnerships for delivery of benefits to some of the least accessible poor people in the wildest places of the world

Using satellite data to develop environmental indicators

Environmental indicators are increasingly being used in policy and management contexts, yet serious data deficiencies exist for many parameters of interest to environmental decision making. With its global synoptic coverage and the wide range of instruments available, satellite remote sensing has the potential to fill a number of these gaps, yet their potential contribution to indicator development has largely remained untested. In this paper we present results of a pilot effort to develop satellite-derived indicators in three major issue areas: ambient air pollution, coastal eutrophication, and biomass burning. A primary focus is on the vetting of indicators by an advisory group composed of remote sensing scientists and policy makers