At a time when agricultural experts are getting hot under the collar about an Indian village whose claims to be smashing rice-growing records have been extolled here and debunked here, it is useful to have a cool global appraisal of the state of genetically-modified (GM) crops, traditionally seen as most likely source of a new green revolution or (alternatively) as a disaster in embryo. Each year the International Service for the Acquisition of Agri-Biotech Applications (ISAAA), a not-for-profit body, publishes estimates for the number of hectares under GM crops (available for order here). Its most recent report shows that, for the first time, developing countries are growing more hectares of GM crops than rich countries are—a remarkable uptake given that the technology was introduced only two decades ago, and is often seen as suitable mainly for rich farmers.

According to ISAAA, 170m hectares of land are planted to GM crops round the world and 52% of them are in emerging markets. Almost half of that share are in five countries, China, India, South Africa, Brazil and Argentina. Brazil is the most important of these: its GM land area rose by more than a fifth in 2012 to 37m hectares, making it the fastest growing GM market in the world and second in size behind America.

Rich countries are using more GM crops, too, but only slightly: they planted 1.6m hectares more than in 2011, up 3%. Developing countries planted 11% more (9m hectares). Of the 17m farmers who use such crops round the world, 15m are in emerging markets.

The report also logs the spread of so-called “stacked traits”, crops with two or more bio-engineered traits. These are planted on 44m hectares, more than a quarter of the total.

Many greens continue to be implacably opposed to GM crops, which they regard as environmentally harmful. This year’s ISAAA report tries to calculate the effects of GM crops on the environment. It says they saved the equivalent of 473m kilograms of pesticides in 2011 (because GM makes crops resistant to pests); saved 109m hectares of new land being ploughed up (GM crops are usually higher-yielding so less land is required for the same output) and reduced greenhouse-gas emissions by 23 billion kg of carbon dioxide equivalent.

GM crops in general need fewer field operations, such as tillage. Reducing tillage allows more residue to remain in the ground, sequestering more CO2 in the soil and reducing greenhouse gas emissions. Fewer field operations also means lower fuel consumption and less CO2.

Greens won’t believe these claims and will probably point out that ISAAA gets money from Monsanto and other GM companies. But that is not a good enough reason to dismiss them (and anyway ISAAA also gets money from governments and the UN). The underlying claim that GM crops reduce carbon emissions seems strong.