Times have changed since stretches of the River Thames were declared "biologically dead" in the 1950s. A colony of seahorses was revealed to have made the London waterway its home this week, joining more than 100 species of fish, dolphins, seals, porpoises and the occasional whale spotted in the murky waters in recent years.

The German government has been forced into an embarrassing climbdown over its plans to lead a worldwide biofuels revolution on the roads after the discovery that too many cars would be unable to run on the proposed ethanol-petrol mix. The environment minister, Sigmar Gabriel, had planned to introduce the new fuel to motorists next year. It is known as E-10, and 90% of it would consist of petrol and the rest of ethanol.

Simon Jenkins thinks that we need to "make today's cities work better" to preserve the countryside and reduce emissions (Eco-towns are the greatest try-on in the history of property speculation, April 4). He's right. If the government wants to get serious about climate change, and deliver 3m new homes over the next two decades, it will take far more than a handful of small, new eco-settlements. However, there's also an economic - as well as an environmental - case for promoting denser, low-carbon city neighbourhoods.

US scientists have unveiled a new, high-resolution interactive map which tracks patterns of CO2 emissions coming from fossil fuels burned daily across the country. The maps and system, called Vulcan, show CO2 emissions in more than 100 times greater detail than was previously available. Until now, scientists say, data on carbon dioxide emissions was reported monthly at a statewide level.

Just when you thought it couldn't get any worse, here comes along James Hansen, head of the Nasa Goddard Institute for Space Studies and one of the world's most respected climate scientists (except in the White House), with an even more depressing assessment of how climate change will unravel over the coming decades - if, that is, we don't act fast to reduce our greenhouse gas emissions.

The discovery of a colony of short-snouted seahorses (Hippocampus hippocampus) living in the Thames means that the London river is becoming cleaner, conservationists said today. Scientists from the Zoological Society of London (ZSL) have discovered five seahorses during routine conservation surveys in the Thames estuary in the past 18 months, evidence which they say indicates that a breeding population exists.

Utilities in Britain and four other European countries stand to gain windfall profits of up to

Energy companies are planning to revive a polluting technology developed by the Nazis to replace dwindling supplies of oil with synthetic fuels derived from coal. Senior industry figures told a high-level conference in Paris this week that coal-to-liquids (CTL) technology could fuel cars and aircraft for decades to come. Green campaigners reacted with alarm because the process produces twice as much greenhouse gas as using oil. Supporters say much of the carbon pollution could be captured and stored underground, and that the synthetic fuel burns cleaner than conventional diesel.

A spring gale is lashing orthodox climate policy. This week, an article was published in Nature that should shake the certainty of anyone who assumes that the Kyoto protocol approach is the sensible way to go, and that signing the accord is a responsible step for the United States to take.

A wildlife conservation scheme in Cambodia staffed by poachers-turned-gamekeepers has led to a dramatic recovery of the endangered bird population on Tonle Sap lake. Seven species of water birds - the spot-billed pelican, milky stork, painted stork, lesser adjutant, greater adjutant, black-headed ibis and Oriental darter - increased up to 20-fold at Prek Toal at the edge of the lake, the region's largest freshwater reservoir which holds the largest - in some cases only - breeding populations of the large water birds.