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Abstract. The rapid rise of global temperature that began about 1975 continues at a mean rate of about 0.18 °C/decade, with the current annual temperature exceeding +1.25 °C relative to 1880–1920. Global temperature has just reached a level similar to the mean level in the prior interglacial (Eemian) period, when sea level was several meters higher than today, and, if it long remains at this level, slow amplifying feedbacks will lead to greater climate change and consequences. The growth rate of climate forcing due to human-caused greenhouse gases (GHGs) increased over 20 % in the past decade mainly due to resurging growth of atmospheric CH4, thus making it increasingly difficult to achieve targets such as limiting global warming to 1.5 °C or reducing atmospheric CO2 below 350 ppm. Such targets now require "negative emissions", i.e., extraction of CO2 from the atmosphere. If rapid phasedown of fossil fuel emissions begins soon, most of the necessary CO2 extraction can take place via improved agricultural and forestry practices, including reforestation and steps to improve soil fertility and increase its carbon content. In this case, the magnitude and duration of global temperature excursion above the natural range of the current interglacial (Holocene) could be limited and irreversible climate impacts could be minimized. In contrast, continued high fossil fuel emissions by the current generation would place a burden on young people to undertake massive technological CO2 extraction, if they are to limit climate change. Proposed methods of extraction such as bioenergy with carbon capture and storage (BECCS) or air capture of CO2 imply minimal estimated costs of 104–570 trillion dollars this century, with large risks and uncertain feasibility. Continued high fossil fuel emissions unarguably sentences young people to either a massive, possibly implausible cleanup or growing deleterious climate impacts or both, scenarios that should provide both incentive and obligation for governments to alter energy policies ...

Abstract. The rapid rise of global temperature that began about 1975 continues at a mean rate of about 0.18 °C/decade, with the current annual temperature exceeding +1.25 °C relative to 1880–1920. Global temperature has just reached a level similar to the mean level in the prior interglacial (Eemian) period, when sea level was several meters higher than today, and, if it long remains at this level, slow amplifying feedbacks will lead to greater climate change and consequences. The growth rate of climate forcing due to human-caused greenhouse gases (GHGs) increased over 20 % in the past decade mainly due to resurging growth of atmospheric CH4, thus making it increasingly difficult to achieve targets such as limiting global warming to 1.5 °C or reducing atmospheric CO2 below 350 ppm. Such targets now require "negative emissions", i.e., extraction of CO2 from the atmosphere. If rapid phasedown of fossil fuel emissions begins soon, most of the necessary CO2 extraction can take place via improved agricultural and forestry practices, including reforestation and steps to improve soil fertility and increase its carbon content. In this case, the magnitude and duration of global temperature excursion above the natural range of the current interglacial (Holocene) could be limited and irreversible climate impacts could be minimized. In contrast, continued high fossil fuel emissions by the current generation would place a burden on young people to undertake massive technological CO2 extraction, if they are to limit climate change. Proposed methods of extraction such as bioenergy with carbon capture and storage (BECCS) or air capture of CO2 imply minimal estimated costs of 104–570 trillion dollars this century, with large risks and uncertain feasibility. Continued high fossil fuel emissions unarguably sentences young people to either a massive, possibly implausible cleanup or growing deleterious climate impacts or both, scenarios that should provide both incentive and obligation for governments to alter energy policies without further delay.

The impacts of a warming world are affecting food production in every corner of the globe. From shifting rainfall patterns and growing seasons, to more frequent and extreme droughts and floods, to increasingly severe pest and disease outbreaks among crops and livestock, farming as we know it is under attack. Globally, agricultural production has fallen by 1-5 percent each decade for the past 30 years, with tropical regions the hardest hit. In 2017, according to the UN Food and Agriculture Organization (FAO), droughts, floods and delayed growing seasons helped trigger food crises in Central America, East and West Africa, and parts of Asia. Yet far worse outcomes are likely ahead for vulnerable food consumers and producers as these climate change impacts intensify and the world's population climbs—if we persist with a business as usual approach. The implication is clear. The agricultural development community must urgently come together around a comprehensive and accelerated adaptation roadmap for food production acknowledging that major transitions across the agriculture sector will be needed. This report seeks to lay the groundwork for a way forward. It brings together academic research, examples of proven adaptive technologies and practices, and lessons learned from practitioners including government, farming communities and the private sector. It then provides recommendations for the development of new technologies and practices and on how to scale what's already working to drive global climate-resilient transitions. The report focuses on agriculture, primarily in the developing world, recognizing that this is only a part of a larger and more complex set of issues related to food systems and their transformation for sustainability. The report identifies a range of adaptive farming technologies and practices that are proven to work and suitable for scaling. These include stress tolerant crops and livestock breeds, sustainable forms of farming intensification, and better risk management through innovations like climate information systems and index-linked insurance. As policy makers, farmers, scientists, civil society organizations and others trial these and other adaptation practices around the world, important lessons for success are emerging that should inform future efforts.

Adaptation to anthropogenic climate change is the biggest challenge that humankind faces. The Intergovernmental Panel on Climate Change (IPCC) provides a synthesis of the state of the science, impacts, and policy, with a focus on long-term climate trends. However, the worst impacts of climate change are likely to come from its exacerbation of weather and climate variability. For example, higher temperatures in a particular region could lead to harsher droughts and more deadly heat waves. These are also the kinds of hazards that are regularly monitored and forecast by governments and institutions at the national, regional, and international scale. This paper argues that climate services are a critical component of adaptation. Communities that benefit from climate services will be better adapted to long-term climate change as well as the weather events and the year to-year variability it could make worse. Climate services involve the production, translation, transfer, and use of climate knowledge and information in relevant decision-making, policy and planninga. They involve far more than climate data, encompassing an understanding of the needs of decision makers and delivering useful information in ways it can be applied for better results. A well-functioning climate service can help decision-makers understand, anticipate, and manage climate-related risks across the range of relevant time scales, from days to decades, much in the way a national meteorological service (NMS) does for weather. Yet, in most of the world, climate services are not sufficiently developed, nor are they properly aligned with the needs of decision-makers in the sectors and systems that are most at risk. The urgency of the climate challenge calls for a critical examination of the current state of climate services relative to the needs of decision-makers; it also requires aggressive action to address long-standing obstacles to meeting those needs. While several decades of research, investment, and implementation provide a strong foundation for climate services, more deliberate action is needed to position climate services as essential to adaptation.

The Democratic Republic of the Congo (DRC) harbors 11% of global malaria cases, yet little is known about the spatial and genetic structure of the parasite population in that country. We sequence 2537 Plasmodium falciparum infections, including a nationally representative population sample from DRC and samples from surrounding countries, using molecular inversion probes - a high-throughput genotyping tool. We identify an east-west divide in haplotypes known to confer resistance to chloroquine and sulfadoxine-pyrimethamine. Furthermore, we identify highly related parasites over large geographic distances, indicative of gene flow and migration. Our results are consistent with a background of isolation by distance combined with the effects of selection for antimalarial drug resistance. This study provides a high-resolution view of parasite genetic structure across a large country in Africa and provides a baseline to study how implementation programs may impact parasite populations.