In June 2009, a group of experts in climate science, crop modeling, and crop development gathered at Stanford University to discuss the major needs for successful crop adaptation to climate change. To focus discussion over the three day period, the meeting centered on just three major crops – rice, wheat, and maize – given that these provide the bulk of calories to most populations. The meeting also focused on two aspects of climate– extreme high temperatures and extreme low moisture conditions (i.e. drought) – that present substantial challenges to crops in current climate and are likely to become more prevalent through time. Other aspects of climate change such as more frequent flooding or saltwater intrusion associated with rising sea levels were not addressed, although they may also be important.

The current document is split into two sections:

• a brief summary of material presented at the meeting on the current state of climate projections, crop modeling, crop genetic resources and breeding; and
  
• the collective views of participants on major needs for future research and investment, which emerged from discussions over the three day meeting.
  

The main target audiences for the document are donor institutions seeking to invest in climate adaptation, and climate and crop scientists seeking to set research agendas. We intend the term donor institutions to include private foundations, governments, and inter‐governmental organizations such as the World Bank and United Nations. An underlying assumption of the Stanford meeting was that there is a real and growing need to identify specific investment opportunities that will improve food security in the face of climate change. This is reflected, for instance, by the recent G8 announcement of a $20B investment in food security, the expectation of additional resources for adaptation from the Copenhagen Conference in 2009, and the emphasis of the Obama administration on food and climate issues.

Nutrient cycles link agricultural systems to their societies and surroundings; inputs of nitrogen and phosphorus in particular are essential for high crop yields, but downstream and downwind losses of these same nutrients diminish environmental quality and human well-being. Agricultural nutrient balances differ substantially with economic development, from inputs that are inadequate to maintain soil fertility in parts of many developing countries, particularly those of sub-Saharan Africa, to excessive and environmentally damaging surpluses in many developed and rapidly growing economies. National and/or regional policies contribute to patterns of nutrient use and their environmental consequences in all of these situations. Solutions to the nutrient challenges that face global agriculture can be informed by analyses of trajectories of change within, as well as across, agricultural systems.

This paper is part 2 of a two-part study evaluating the climatic effect of one of the nation's most rapidly expanding metropolitan complexes, the Greater Phoenix, Arizona, region.

Part 1, using a set of sensitivity experiments, estimated the potential impact of observed landscape evolution, since the dawn of the Landsat satellite era on the near surface climate, with a primary focus on the alteration of the surface radiation and energy budgets and through use of high-resolution, 2km grid spacing, Regional Atmospheric Modeling System (RAMS) simulations with circa 1973, circa 1992, and circa 2001 landscape data sets.

In this paper, part 2, we address the role of the previously discussed surface budget changes and subsequent repartitioning of energy on the mesoscale dynamics and thermodynamics of the region, the effect on convective rainfall, and their association with the large-scale North American Monsoon System (NAMS). Our results show that contrasts in surface heating resulting from landscape change are responsible for the development of preferentially located mesoscale circulations, on most days, which were stronger for the 2001 compared to the 1973 landscape, due to increased planetary boundary layer (PBL) heating via enhanced turbulent heat flux.

The effect of these stronger circulations was to warm and dry the lower part of the PBL and moisten the upper part of the PBL for the 2001 relative to the 1973 landscape. The precise physical pathway(s) whereby precipitation enhancement is initiated with evolving landscape, since the early 1970s, reveals a complicated interplay among scales (from the turbulent to the synoptic scale) that warrants future research. Precipitation recycling, however, was found to be an important driver in the overall sustenance of rainfall enhancement.

Although this study was not designed to investigate other radiative forcing factors such as greenhouse gas emissions and aerosols, the results of our sensitivity experiments do suggest that regional land use change is an important element of climate change in semiarid environments characterized by large urban areas with scarce water resources.

This chapter looks more qualitatively at Asia as a single region and focuses more speculatively on the longer run. It is also more personal, since views of the 2025, like beauty, depend inevitably on the eyes of the beholder. The chapter begins by running history backwards via a thought experiment. Suppose in 1975 that one had been predicting the contours of the Asian maize economy in 2000. What variables and parameters would forecasters have missed in significant ways? This procedure turns out to be a very sobering exercise for anyone now predicting events in 2025.