Impatti, adattamento e vulnerabilita Le cause e le responsabilita dei cambiamenti climatici sono state trattate sul numero di ottobre della rivista Cda. Approfondiamo l’argomento presentando il documento: “Cambiamenti climatici 2007: impatti, adattamento e vulnerabilita” votato ad aprile 2007 dal secondo gruppo di lavoro del Comitato Intergovernativo sui Cambiamenti Climatici (Intergovernmental Panel on Climate Change). Si tratta del secondo di tre documenti che compongono il quarto rapporto sui cambiamenti climatici.

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Climate Change 2007: Impacts, Adaptation and Vulnerability.

This paper describes the scenario matrix architecture that underlies a framework for developing new scenarios for climate change research. The matrix architecture facilitates addressing key questions related to current climate research and policy-making: identifying the effectiveness of different adaptation and mitigation strategies (in terms of their costs, risks, and other consequences) and the possible trade-offs and synergies. The two main axes of the matrix are: (1) the level of radiative forcing of the climate system (as characterized by the representative concentration pathways), and (2) a set of alternative plausible trajectories of future global development (described as shared socio-economic pathways). The matrix can be used to guide scenario development at different scales. It can also be used as a heuristic tool for classifying new and existing scenarios for assessment. Key elements of the architecture, in particular the shared socio-economic pathways and shared policy assumptions (devices for incorporating explicit mitigation and adaptation policies), are elaborated in other papers in this special issue.

A new scenario framework for climate change research : scenario matrix architecture

There has always been an uneasy relationship between 'urban' planning and agricultural production. The practice of planning, born and raised in an urban environment, is prone to misunderstand the culture and complexity of rural areas. It has sought to apply urban values, approaches and systems, in an effort to reduce complexity and tame the frontier.

The Food Security Challenge

Nanofertilizers for agricultural and environmental sustainability

The demand for biofuels is expected to increase significantly in the coming years. However, there are major concerns on the impact of increased biofuel production on food security. As biofuel affects food security in various ways, it is important to assess the impacts on the four pillars of food security, availability, access, utilisation and stability. The objective of this study is to ex-ante quantify impacts of biofuel production on the four pillars of food security for urban and rural households in a developing country. We illustrate this for Ghana, which proposed a 10% biodiesel and 15% ethanol mandate for 2030 and which faces food security issues. We used the computable general equilibrium (CGE) model MAGNET in combination with a household and a nutrition module to quantify 13 food security indicators. The results show that the largest food security effects of the biofuel mandate are negative impacts on food prices and import dependency. However, the projected food security impacts of the biofuel mandate in 2030 are relatively small compared to the projected food security effects of economic development in Ghana towards 2030. Our approach enables ex-ante quantification of the effects of biofuel on the four pillars of food security and the differentiation of the effects between urban and rural households. Although improvements can be made, the approach means a big step forward compared to the state-of-the-art knowledge on food security impacts of biofuel production and it could contribute to identify options to minimise negative and optimise positive food security effects.

The distribution of food security impacts of biofuels, a Ghana case study

Quantified global scenarios and projections are used to assess long-term future global food security under a range of socio-economic and climate change scenarios. Here, we conducted a systematic literature review and meta-analysis to assess the range of future global food security projections to 2050. We reviewed 57 global food security projection and quantitative scenario studies that have been published in the past two decades and discussed the methods, underlying drivers, indicators and projections. Across five representative scenarios that span divergent but plausible socio-economic futures, the total global food demand is expected to increase by 35% to 56% between 2010 and 2050, while population at risk of hunger is expected to change by −91% to +8% over the same period. If climate change is taken into account, the ranges change slightly (+30% to +62% for total food demand and −91% to +30% for population at risk of hunger) but with no statistical differences overall. The results of our review can be used to benchmark new global food security projections and quantitative scenario studies and inform policy analysis and the public debate on the future of food.

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A meta-analysis of projected global food demand and population at risk of hunger for the period 2010–2050

Can yield variability be explained? Integrated assessment of maize yield gaps across smallholders in Ghana.


 Ending hunger and achieving food security - one of the UN sustainable development goals - is a major global challenge. To inform the policy debate, quantified global scenarios and projections are used to assess long-term future global food security under a range of socio-economic and climate change scenarios. However, due to differences in model design and scenario assumptions, there is uncertainty about the range of food security projections and outcomes. We conducted a systematic literature review and meta-analysis to assess the range of future global food security projections to 2050. We reviewed 57 global food security projection and quantitative scenario studies that have been published over the last two decades and discussed the methodology, underlying drivers, indicators and projections. We harvested quantitative information from 26 studies to compare future trends of the two most used global food security indicators: per capita food demand (593 projections) and population at risk of hunger (358 projections). We found that across five representative scenarios that span divergent but plausible socio-economic futures total global food demand is expected to increase by +35% to +56% between 2010 and 2050, while population at risk of hunger is expected to change by -91% to +8% over the same period. If climate change is taken into account the range changes slightly (+30% to +62% for total food demand and -91% to +30% for population at risk of hunger) but overall we do not find statistical support for differences in projections with and without climate change. Finally, our review suggests that current modeling approaches can be improved by better incorporating several options that have been proposed to tackle global food security, in particular aquaculture and ‘future foods’, and expand the number of indicators to better cover the multiple dimensions of food security. The results of our review can be used to benchmark new global food security projections and quantitative scenario studies and inform policy analysis and the public debate on the future of food.

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Tom Morley

Papers

A meta-analysis of projected global food demand and population at risk of hunger for the period 2010–2050

Can yield variability be explained? Integrated assessment of maize yield gaps across smallholders in Ghana.

Systematic review and meta-analysis of global food security projections to 2050