Climate science

Tackle air pollution to kickstart climate action, says new study

  • 19 Nov 2014, 18:00
  • Roz Pidcock

Air pollution is a huge problem worldwide, killing millions of people each year. Further warming will only increase the size of the problem, according to a Nature article today.

It's time efforts to curb soot, ozone and other pollutants in the atmosphere got more attention at an international level, the researchers argue.

Getting serious about air pollution could provide the impetus needed to tackle climate change more effectively.

Airborne killers

Methane, ozone, nitrogen dioxide and soot (or black carbon) all contribute to poor air quality.

Air pollution is already the  leading environmental cause of ill-health, leading to about seven million premature deaths each year from respiratory and circulatory illnesses.

Earlier today, the European Council  ruled the UK must take urgent action to address dangerous levels of air pollution. A number of major cities, including London, are lagging behind targets to reduce nitrogen dioxide to legal limits by the January 2015 deadline.

The burden of ill-health is  likely to increase in cities by mid century, as air pollution interacts with further greenhouse gas warming, research shows.

Compounds Of Concern _Schmale

Impacts of common air pollutants for human health, the climate and agriculture. Source: Schmale et al. (2014)

more

How small volcanic eruptions may have slowed surface temperature rise

  • 19 Nov 2014, 17:20
  • Robert McSweeney

Scientists have been underestimating the influence of small volcanic eruptions on the climate system, a new study argues.

The findings could help explain why recent warming at the Earth's surface has been slower than in previous decades, the researchers say.

A cataclysmic event

In June 1991 Mount Pinatubo in the Philippines erupted, sending a cloud of ash, dust and sulphur dioxide 35 kilometers into the atmosphere.

That sulphur dioxide combined with oxygen and water to form sulphuric acid aerosols. These particles reflected sunlight and encouraged clouds to form, cooling parts of the world by up to 0.4°C for two years after the eruption.

Volcanic eruptions are rated from zero to eight on a scale of explosivity, measured by the amount of ash and debris they produce. The Pinatubo eruption was rated as a five, or 'cataclysmic'.

While the world hasn't seen such a huge volcanic eruption since, on average there is one small eruption somewhere in the world every week. A new study, published in Geophysical Research Letters, finds that these smaller eruptions may together have a bigger impact on global climate than previously thought.

Pinatubo _ash _plume _910612

more

Why feeding more people doesn't have to be at the expense of the climate

  • 18 Nov 2014, 16:14
  • Robert McSweeney

The world is on course to produce more wheat this year than ever before. Yet as supply rises to meet demand, so do the carbon emissions from growing and harvesting the crop.

Now a 25-year long field experiment in Canada shows that growing wheat can actually take up more carbon than it releases. Meeting demand for food doesn't have to mean more carbon emissions, the study's lead scientist tells us.

Wheat is in demand

Wheat is the third most-grown cereal crop in the world, after maize and rice. Demand for major cereal crops such as wheat is expected to increase by 70 percent by 2050.

In the UK, around two million hectares of land are used to grow wheat, with the harvested crop worth around £1.2 billion. But wheat accounts for 30 per cent of emissions from growing the crops we eat, estimates WWF.

Fuel burned in tractors used to farm land releases carbon dioxide, as does producing and using fertilisers. These emissions typically outweigh the amount of carbon dioxide the crops absorb as they grow.

Now a new study by Canadian researchers, published in Nature Communications, finds that with some changes to farming practices, growing wheat can actually remove more carbon dioxide from the atmosphere than it produces.

Little field on a prairie

The US and Canada are the third and fifth largest producers of wheat in the world. Between them they harvested around 90 million tons of wheat last year. Most of this is grown in the 'wheat belt', a vast area of the North American prairies that stretches across much of central US and Canada.

more