By 2050 it is expected that there will be around nine billion people in the world, more than two billion more than at present. Can they be fed? And can they be fed if climate change is to be limited to two degrees of global warming or less?

The former question has received considerable attention, the latter much less so. This has produced a notable gap between, on the one hand, arguments that stress the need for farmers in the developing world to raise production through higher yields per unit, relying heavily on increased irrigation, fertiliser application and intensive livestock production; and, on the other hand, the need for agriculture with lower net emissions.

Currently farming contributes more than 27% of the emissions of greenhouse gases (GHG), mainly from the use of fertilisers, fossil fuels for power on farms, numbers and management of ruminant livestock and flooded rice fields, and the conversion of habitats such as forest or peat land to fields and pastures that typically releases large amounts of carbon into the atmosphere. If climate change is to be mitigated sufficiently, then the practices that lead to such large emissions need changing.

There are, moreover, opportunities as well: since some farming systems sequester more carbon than others, there is scope not only to reduce emissions from farms but also to increase carbon storage, thereby cutting net emissions from agriculture to low levels — conceivably to zero.

But what would agriculture that mitigated climate change, and still fed nine billion in 2005, look like? What options are there for modifying existing farming systems and developing novel ones?

These are the questions this short review of the literature addresses. This paper is based on a review of existing sources and consulting some key informants.