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. Pakistan is a country with the second highest number of children out of school in the world. It has some of the worst nutrition, maternal mortality and child health indicators.

Just 227 tree species dominate Amazon

Researchers were surprised to find that such a small proportion of species dominated the Amazon . Despite being home to about 16,000 tree species, just 227 "hyperdominant" species account for half of Amazonia's total trees, a study suggests. An international team of researchers found that the region was, in total, home to an estimated 390 billion trees. Writing in Science, they added that the rarest 11,000 species made up only 0.12% of tree cover. However, they added that the new data could help unlock ecological secrets held by the biodiversity hotspot.

The results were based on a survey of 1,170 plots and half-a-million trees across the six-million-square-kilometre area, often described as the lungs of the world. The authors said that the underlying cause of the hyper dominance of the 227 species, which accounted for 1.4% of the estimated number of species in the region, remained unknown. "We knew that, normally, a few species dominate ecosystems, but if you have a system that has 16,000 tree species but just 227 make up half of the trees, that was pretty surprising even for us," said lead author Dr Hans ter Steege from the Naturalis Biodiversity Center in the Netherlands. He told the Science podcast: "We don't really know why these species are so incredibly dominant because they do not have any particular ecological feature that stands out."

Corals are likely to suffer as a result of the changes to our oceans The health of the world’s oceans is deteriorating even faster than had previously been thought, a report says. A review from the International Programme on the State of the Ocean (IPSO), warns that the oceans are facing multiple threats. They are being heated by climate change, turned slowly less alkaline by absorbing CO2, and suffering from overfishing and pollution. The report warns that dead zones formed by fertiliser run-off are a problem. It says conditions are ripe for the sort of mass extinction event that has afflicted the oceans in the past. It says: “We have been taking the ocean for granted. It has been shielding us from the worst effects of accelerating climate change by absorbing excess CO2 from the atmosphere. “Whilst terrestrial temperature increases may be experiencing a pause, the ocean continues to warm regardless. For the most part, however, the public and policymakers are failing to recognise - or choosing to ignore - the severity of the situation.” It says the cocktail of threats facing the ocean is more powerful than the individual problems themselves. Coral reefs, for instance, are suffering from the higher temperatures and the effects of acidification whilst also being weakened by bad fishing practices, pollution, siltation and toxic algal blooms. IPSO, funded by charitable foundations, is publishing a set of five papers based on workshops in 2011 and 2012 in partnership with the International Union for Conservation of Nature (IUCN’s) World Commission on Protected Areas.

Indian tigers face threat due to lack of genetic diversity.

Tigers need genetic diversity to survive. India's tigers are facing extinction owing to a collapse in the variety of their mating partners, say Cardiff University researchers. They found that 93% of DNA variants found in tigers shot the period of the British Raj were not present in tigers today Prof Mike Bruford said the genetic diversity needed for the species to survive had been "lost dramatically".

There are fewer than 2,000 tigers left worldwide, 60% in India. The Cardiff university team collaborated with the National Centre for Biological Sciences in Bangalore, India on the research. They had unprecedented access to the Natural History Museum of London's tiger collection which allowed them to identify the DNA variants in the tigers killed in the British Raj period from 1858 to 1947 but which have disappeared today. Mechanised trophy hunting reduced the animal's numbers from 40,000 in a mere 100 years. The territory occupied by the tiger has declined more than 50% during the last three generations and mating now only occurs in 7% of its historical territory.

Nicaragua cloud forest 'under siege' by illegal loggers. Bosawas forest - the Bosawas Reserve is a critically important rainforest but native people say it is being destroyed by "colonists" A famed rainforest in Nicaragua is under growing threat from illegal loggers, say indigenous leaders. The Bosawas Biosphere Reserve is Central America's largest tropical forest with clouds constantly drifting over the hilly terrain. But the Mayangna and Miskito people who live there say 30,000 hectares a year are being deforested by "colonists". They are calling on US president Barack Obama, who is visiting the region, to support their battle. Described by the United Nations as a global biological treasure, the reserve is located on the border between Nicaragua and Honduras and teems with wildlife. “We believe that if there is no intervention there will be no Biosphere Reserve in five to 10 years” Taymond Robins, Mayangna people The two million hectares are said to be home to 150,000 insect species, rare jaguars, eagles and crocodiles as well as the world's last populations of Baird's Tapir and the Central American Spider Monkey. Landless invaders The Bosawas reserve also overlaps the homes of indigenous communities who have been there for centuries, living by hunting and fishing. The Nicaraguan government recognised the full legal title of the Mayangna to their lands in 2007. Since then, they say they have been subject to what they term an "invasion" by landless people from other parts of the country.