The ocean response to climate change guides both adaptation and mitigation efforts

The ocean’s thermal inertia is a major contributor to irreversible ocean changes exceeding time scales that matter to human society.This fact is a challenge to societies as they prepare for the consequences of climate change,especially with respect to the ocean.Here the authors review the requirements for human actions from the ocean’s perspective.In the near term(∼2030),goals such as the United Nations Sustainable Development Goals(SDGs)will be critical.Over longer times(∼2050–2060 and beyond),global carbon neutrality targets may be met as countries continue to work toward reducing emissions.Both adaptation and mitigation plans need to be fully implemented in the interim,and the Global Ocean Observation System should be sustained so that changes can be continuously monitored.In the longer-term(after∼2060),slow emerging changes such as deep ocean warming and sea level rise are committed to continue even in the scenario where net zero emissions are reached.Thus,climate actions have to extend to time scales of hundreds of years.At these time scales,preparation for“high impact,low probability”risks—such as an abrupt showdown of Atlantic Meridional Overturning Circulation,ecosystem change,or irreversible ice sheet loss—should be fully integrated into long-term planning.

Hallmark of a Resilient City: Adoption of Green Infrastructure in African Cities

Dynamic urbanization of African cities has created development trajectories that face systemic challenges in the provision of sustainable and ecologically resilient urban environments. The specific challenges include extensive unregulated growth with informal settlements reflecting poor service levels and high poverty indices, inadequacy in provision of basic services in health, water, housing, transport and communication infrastructure, high reliance on biomass fuels, exposure to environmental stress and implausible climate change coping and mitigation mechanisms among others. Review of extensive literature and synthesis of existing bodies of knowledge on the ecological and management perspectives of urban environments revealed many gaps and understanding of urban transformation processes. The purpose of this review was to contextualize credible pathways for optimization of both ecosystem goods and services from green urban landscapes (Green infrastructure) and non-green infrastructure to ensure sustainable and ecologically resilient urban environments. Attempts were made to rationalize and validate through discussions the benefits of managed urban ecosystems for African cities. On the basis of the evidence from the literature, it is concluded that urban development trajectories that do not embrace multifaceted approaches that deliberately retain and maintain green infrastructure in the urban environment may not be cost-effective. It is recommended that systematic integration of urban forestry concepts in urban planning that involves communities, local and national governments, business entrepreneurs and public and private research institutions provides tenable frameworks for addressing current and future challenges of urbanization in Africa.

Climate change and multi-dimensional sustainable urbanization

Global large-scale urbanization and climate change have become indisputable scientific facts yet are unresolved issues,and are a common concern for mankind.The relationship between these two topics is unclear and it is not known how to deal appropriately at the scientific level with climate change in the process of urbanization.Further exploration of the science,management and practice,are needed to achieve global and regional sustainadevelopment.This paper first considers the basic facts concerning mass urbanization and climate change and summarizes the interactions and possible mechanisms of urbanization and climate change.Urbanization leads to the heat island effect,an uneven distribution of precipitation and extreme weather,together with a local-regional-global multi-scale superposition effect,which aggravates the consequences of global climate change.The impact of climate change on urbanization is mainly manifested in aspects such as changes of energy consumption,mortality,and the spread of infectious diseases,sea level rise,extreme weather damage to infrastructure,and water shortages.This paper also briefly reviews relevant international research programs and action coalitions and puts forward an analysis framework multi-dimensional sustainable urbanization which can adapt to and mitigate climate change,from the perspective of the four key dimensions—population,land use,economy,and society.It is imperative that we strengthen the interdisciplinary activities involving the natural and social sciences,take urbanization and other human activities into consideration of the land-atmosphere system,and explore the human-land-atmosphere coupling process.The adaptation and mitigation from the perspective of human activities,as represented by urbanization,might be the most critical and realistic way to deal with climate change.