Vaccination is one of medicine's greatest achievements, so why do so many people fear it? : a report

The cluster of beige corrugated-iron sheds and silos don't look like much, but this unassuming factory in a suburb of Melbourne, Australia, represents a potential revolution in greenhouse gas emissions. It's the first commercial enterprise in the world dedicated to transforming waste from power stations and blast furnaces into geopolymer concrete, a particularly promising green concrete.

Perhaps genetic engineering could help to increase the efficiency with which crops absorb nitrate from soil (5 January, p 28). However, the claim by Arcadia Biosciences that this will substantially cut agricultural emissions of the greenhouse gas nitrous oxide appears Utopian rather than Arcadian. (Letters)

"We apologise for recent price increases," reads the sign over the bread counter, "but they are due to global factors beyond our control." This is not a Third World food stall but an upscale supermarket in Brussels, capital of the European Union, whose farming system was once notorious for the mountains of surplus grain it produced. Those mountains are now gone. The world is down to its lowest grain stocks for decades, and food prices are up around the world.

Living close to a busy road can damage your heart - and now we're closer to understanding why. Previous studies had suggested that people living in polluted areas are more at risk of heart disease.

Contrary to what it says in the song, the rain in Spain does not stay mainly in the plain. It falls mostly in the mountainous regions of Cantabria and Asturias. Ask meteorologists why, and they will explain that the prevailing winds pick up moisture over the Atlantic, and that when this moist air hits Spain's northern mountain ranges it is forced up to higher altitudes, where the moisture condenses to form clouds, and then rain. So far so good - except that it's only half an answer.

Farming contributes more to global warming than all the world's cars, trains, ships and planes put together. And the single biggest problem with farming is not carbon but nitrogen. From the maize fields of Kansas to the emerald rice paddies of China, today's bountiful harvests depend on generous applications of nitrogen fertiliser. Although only a tiny proportion escapes into the atmosphere as nitrous oxide, it is an extremely potent greenhouse gas. It's a vexing problem, but Eric Rey believes he has some of the answers, in the form of crops genetically modified to require less fertiliser.

While cutting down rainforests to grow palm oil for biofuels may constitute "madness" (1 December 2007, p 50), burning other vegetable oils is no more sane, nor less damaging to Indonesia's rainforests. Indonesia is expected to increase its palm oil production by more than half over the next 10 years. This is driven, in part, by China, which used to buy rapeseed oil from Europe for food and for industrial uses, but is switching to Indonesian palm oil because Europe's cars and trucks now burn the rapeseed oil as a biofuel.

One way to cut greenhouse gas levels in the atmosphere may be to exploit a particular talent some plants have of locking away carbon. All we need to do is choose the right strains of crops to grow, and they will sequester carbon for us for millennia. That's the idea of two agricultural scientists in Australia, who say the trick is to grow grasses such as wheat and sorghum, which lock up large amounts of carbon in so-called plantstones, also known as phytoliths.

As the world warms, the plants that billions of people depend on for their food are likely to become less nutritious. That's the worrying conclusion of an analysis of more than 40 studies investigating how crops will react to increasing levels of carbon dioxide in the atmosphere.