2013 warmest on record

The world is spending half a trillion dollars on fossil fuel subsidies every year, according to a new report.

The Overseas Development Institute (ODI) says rich countries are spending seven times more supporting coal, oil and gas than they are on helping poorer nations fight climate change. Fuel subsidies to US farmers amounted to $1bn in 2011 says the ODI. Some countries including Egypt, Morocco and Pakistan, have subsidies bigger than the national fiscal deficit. The new report calls on the G20 to phase out the payments by 2020.

While there is no globally agreed definition of what a fossil fuel subsidy actually is, the report draws on a range of sources from the International Monetary Fund to the International Energy Agency. It details the range of financial help given to oil, coal and gas producers and consumers from national governments and through international development. What emerges is a complicated web of different types of payments in different countries. In the United States, for example, the government in 2011 gave a $1bn fuel tax exemption to farmers, $1bn for the strategic petroleum reserve and $0.5bn for oil, coal and gas research and development. Germany gave financial assistance totalling 1.9bn euro to the hard coal sector in the same year. And the UK gave tax concessions worth £280m in 2011 for oil and gas production.

The WMO says that fossil fuel activities such as oil refining are driving atmospheric levels of CO2 to record highs. The levels of gases in the atmosphere that drive global warming increased to a record high in 2012. According to the World Meteorological Organization (WMO), atmospheric CO2 grew more rapidly last year than its average rise over the past decade. Concentrations of methane and nitrous oxide also broke previous records. Thanks to carbon dioxide and these other gases, the WMO says the warming effect on our climate has increased by almost a third since 1990. The WMO's annual greenhouse gas bulletin measures concentrations in the atmosphere, not emissions on the ground. Carbon dioxide is the most important of the gases that they track, but only about half of the CO2 that's emitted by human activities remains in the atmosphere, with the rest being absorbed by the plants, trees, the land and the oceans. Since the start of the industrial era in 1750, global average levels of CO2 in the atmosphere have increased by 141%. According to the WMO there were 393.1 parts per million (ppm) of carbon dioxide in the atmosphere in 2012, an increase of 2.2ppm over 2011. This was above the yearly average of 2.02ppm over the past decade. "The observations highlight yet again how heat-trapping gases from human activities have upset the natural balance of our atmosphere and are a major contribution to climate change," said WMO Secretary-General Michel Jarraud.

Climate change is helping pests and diseases that attack crops to spread around the world, a study suggests.

Researchers from the universities of Exeter and Oxford have found crop pests are moving at an average of 3km (two miles) a year. The team looked at more than 600 pests, including the Colorado potato beetle.

The team said they were heading towards the north and south poles, and were establishing in areas that were once to cold for them to live in.

The research is published in the journal Nature Climate Change.

Currently, it is estimated that between 10% and 16% of the world's crops are lost to disease outbreaks. The researchers warn that rising global temperatures could make the problem worse.

Dr Dan Bebber, the lead author of the study from the University of Exeter, said: "Global food security is one of the major challenges we are going to face over the next few decades.

"We really don't want to be losing any more of our crops than is absolutely necessary to pests and pathogens."

Trade transport

To investigate the problem, the researchers looked at the records of 612 crop pests and pathogens from around the world that had been collected over the past 50 years.

These included fungi, such as wheat rust, which is devastating harvests in Africa, the Middle East and Asia; insects like the mountain pine beetle that is destroying trees in the US; as well as bacteria, viruses and microscopic nematode worms.

Arctic melt: Increasing temperatures in the Arctic region are reducing sea ice cover and increasing the possibility of methane leaching from the sea bed. Scientists say that the release of large amounts of methane from thawing permafrost in the Arctic could have huge economic impacts for the world. The researchers estimate that the climate effects of the release of this gas could cost $60 trillion (£39 trillion), roughly the size of the global economy in 2012. The impacts are most likely to be felt in developing countries they say. Scientists have had concerns about the impact of rising temperatures on permafrost for many years. Large amounts of methane are concentrated in the frozen Arctic tundra but are also found as semi-solid gas hydrates under the sea. Price of gas Previous work has shown that the diminishing ice cover in the East Siberian sea is allowing the waters to warm and the methane to leach out. Scientists have found plumes of the gas up to a kilometre in diameter rising from these waters. In this study, the researchers have attempted to put an economic price on the climate damage that these emissions of methane could cause. Methane is a powerful greenhouse gas, even though it lasts less than a decade in the atmosphere.