The United Nations chief, Ban Ki-moon, held out little hope on Thursday of an historic outcome at the Rio global development summit, now less than a month away, admitting negotiations had been "painfully slow".

The warning was the latest from United Nations officials and others involved in preparations that the summit, known as Rio+20, is unlikely to replicate the breakthrough achievements of the original environmental gathering in the city in 1992.

The UK is in danger of building too many waste treatment plants and could reach over-capacity by 2015, new research warns.

A study from Eunomia Research & Consulting claims that if all of the facilities which have been granted planning consent are built and if waste arisings remain flat, then the country will have 5m tonnes more capacity than it requires.

The situation will be exacerbated if any plants which are currently in planning or unannounced are also built, or if waste arisings continue to fall, as they have for the past five years.

Tackling polio has entered "emergency mode" according to the Global Polio Eradication Initiative after "explosive" outbreaks in countries previously free of the disease.

It has launched a plan to boost vaccination in Nigeria, Pakistan and Afghanistan, the only countries where the disease is still endemic.

Experts fear the disease could "come back with a vengeance".

The World Health Organization says polio is "at a tipping point".

China spurred a jump in global carbon dioxide (CO2) emissions to their highest ever recorded level in 2011, offsetting falls in the United States and Europe, the International Energy Agency (IEA) said on Thursday.

CO2 emissions rose by 3.2 percent last year to 31.6 billion metric tons (34.83 billion tons), preliminary estimates from the Paris-based IEA showed.

China, the world's biggest emitter of CO2, made the largest contribution to the global rise, its emissions increasing by 9.3 percent, the body said, driven mainly by higher coal use.

Saudi Arabia, the world's top oil exporter, may finally be getting serious about overcoming the technical and financial hurdles for tapping its other main resource: sunshine.

Thousands of solar power panels have sprung up across Europe over the past few years, thanks to generous subsidies that make the technology an attractive alternative to conventional energy.

Saudi Arabia too, wants to generate much more solar power as it lacks coal or enough natural gas output to meet rapidly rising power demand.

Scotland's University of Edinburgh on Wednesday opened a centre to research the use of carbon to retrieve oil otherwise hard to extract from reservoirs, a method which could unlock three billion barrels of trapped North Sea oil worth 190 billion pounds ($300 billion).

A number of developers of carbon capture and storage (CCS) projects have already suggested using the method, also known as enhanced oil recovery (EOR) that has been used in North America for decades, to enhance the economic viability of their plants which are expensive to finance.

Large-scale crop plantations are expanding at a rapid pace across southeast Asia, with multinational firms often benefiting the most at the expense of local communities and the environment, two U.N. rights experts warned on Wednesday.

Demand for agrofuels, such as those derived from sugar cane and palm oil, has boomed thanks in part to the United States, Europe and other rich economies seeking alternative ways to fuel their cars and homes in order to reduce their carbon emissions.

Tough new limits on the maximum sulphur content of shipping fuels will come into effect in Europe at the end of the decade, after EU governments agreed on draft legislation on Wednesday.

Air pollution from marine fuels with a high sulphur content is estimated to cause 50,000 premature deaths a year in Europe, the European Parliament has said.

"This is excellent news for our health and the environment, especially in ports and coastal areas," EU Environment Commissioner Janez Potocnik said in a statement.

Europe yesterday warned at climate talks in Bonn that efforts to forge a new global pact to avert environmental disaster were in danger of floundering, and some pointed fingers at China.

Nine days into talks meant to set the stage for a United Nations gathering in Qatar in December, where countries must adopt an amendment to the Kyoto Protocol on climate change, negotiators complained that procedural bickering was quashing progress hopes.

A 5.6 magnitude earthquake shook Bulgaria's capital Sofia early on Tuesday, causing residents to rush into the streets, the civil defence office said.

The quake, which occurred at 3 a.m. local time, shook apartment buildings and rattled windows but caused no casualties or damage, Nikolay Nikolov, an official from the office was quoted as saying by the national radio, citing initial reports.

The U.S. Geological Survey said the temblor was cantered about 14 miles (24 km) west of Sofia and occurred at a relatively shallow depth of 5.8 miles (9.4 km).