Smallholder farmers have a vital role to play in global food security and nutrition, and in supporting a range of development and climate change goals. Strengthening the resilience and commercial viability of these farmers, particularly women and youth, can increase their capacity to contribute to these global goals.

There are 1.4 billion poor people living on less than US$1.25 a day. One billion of them live in rural areas where agriculture is their main source of livelihood. The ‘green revolution’ in agriculture that swept large parts of the developing world during the 1960s and 1970s dramatically increased agricultural productivity and reduced poverty. Many of the productivity gains accrued to smallholder farmers, supported through research and extension services.

The Paris Agreement, adopted in December 2015, represents a new beginning in the global effort to stabilize the climate before it is too late. It recognizes the importance of food security in the international response to climate change, as reflected by many countries focusing prominently on the agriculture sector in their planned contributions to adaptation and mitigation. To help put those plans into action, this report identifies strategies, financing opportunities, and data and information needs.

Climate change is a significant and growing threat to food security—already affecting vulnerable populations in many developing countries, and expected to affect ever more people in more places, unless action is taken beginning today. Current scenarios for business-as-usual farming under climate change project growing food security challenges by 2050. Worst hit will be underdeveloped regions of the world where food insecurity is already a problem and populations are vulnerable to shocks (Rosegrant et al. 2014).

This document is the result of coordinated and carefully connected cross Working Group efforts to ensure coherent and comprehensive information on various aspects related to climate change. This SYR includes a consistent evaluation and assessment of uncertainties and risks; integrated costing and economic analysis; regional aspects; changes, impacts and responses related to water and earth systems, the carbon cycle including ocean acidification, cryosphere and sea level rise; as well as treatment of mitigation and adaptation options within the framework of sustainable development.

Climate change impacts, adaptation, and vulnerability span a vast range of topics.With the deepening of knowledge about climate change, we see connections in expanding and diverse areas, activities, and assets at risk. Early research focused on direct impacts of temperature and rainfall on humans, crops, and wild plants and animals. New evidence points to the importance of understanding not only these direct impacts but also potential indirect impacts, including impacts that can be transmitted around the world through trade, travel, and security.

Some of the most important impacts of global climate change will be felt among the populations, predominantly in developing countries, referred to as ‘‘subsistence’’ or ‘‘smallholder’’ farmers. Their vulnerability to climate change comes both from being predominantly located in the tropics, and from various socioeconomic, demographic, and policy trends limiting their capacity to adapt to change.

Previous studies have combined climate, crop and economic models to examine the impact of climate change on agricultural production and food security, but results have varied widely due to differences in models, scenarios and input data. Recent work has examined (and narrowed) these differences through systematic model intercomparison using a high-emissions pathway to highlight the differences. This paper extends that analysis to explore a range of plausible socioeconomic scenarios and emission pathways.

Forest cover monitoring plays an important role in the implementation of climate change mitigation policies such as Kyoto protocol and Reducing Emissions from Deforestation and Forest Degradation (REDD). In this study, we have monitored land cover using the PALSAR (Phased Array type L-band Synthetic Aperture Radar) full polarimetric data based on incoherent target decomposition.

Whereas climate change mitigation involving payments to forest landowners for accumulating carbon on their land may increase carbon stored in forests, it will also affect timber supply and prices. This study estimated the effect on US timber and primary forest product markets of hypothetical timber set-aside scenarios where US forest landowners would be paid to forego timber harvests for 100 years to increase carbon storage on US timberland.

Baseflow and precipitation in the Kickapoo River Watershed, located in the Driftless Area of Wisconsin, exhibit a step increase around 1970, similar to minimum and median flows in many other central and eastern USA streams. Potential effects on streamflow due to climatic and land management changes were evaluated by comparing volumetric changes in the hydrologic budget before and after 1970. Increases in precipitation do not fully account for the increase in baseflow, which appears to be offset by a volumetric decrease in stormflow.

Scientists predict that global warming will cause suitable habitat ranges to shift for many plant species, including blue oak in California. If proximity to particular land cover types significantly affects human welfare, any such shifts will affect household welfare, resulting in an indirect cost that is currently unaccounted for in the climate change literature. Using a hedonic pricing model, the marginal values of blue oaks and the land cover types most likely to replace them are estimated at multiple spatial scales using single family residences sold in Kern County from 1997 to 2003.