Scientists, in a world first, announced Wednesday they had added two letters to the genetic code that forms the chemical blueprint for life.

They said they had modified a bacterium so that it incorporated and replicated two DNA ingredients that are not found in nature.

Polar scientists said Thursday they had successfully drilled a 2,000-year-old ice core in the heart of Antarctica in a bid to retrieve a frozen record of how the planet's climate has evolved.

The Aurora Basin North project involves scientists from Australia, China, France, Denmark, Germany and the United States who hope it will also advance the search for the scientific "holy grail" of the million-year-old ice core.

Germany is the European Union's worst polluter, with its production of CO2 gasses from fossil fuel rising by two percent in 2013 to 760 million tonnes, official data showed on Wednesday.

The EU's statistics agency Eurostat found that while emissions were cut across the 28-member bloc by an average of 2.5 percent in 2013, they actually went up in six countries, including Germany.

More than 170 sharks were caught during a controversial cull policy in Western Australia following a spate of fatal attacks, figures showed Wednesday, with 50 of the biggest ones destroyed.

The policy, in place around popular west coast beaches, was given the green light in January after six fatal attacks in the past two years, angering conservationists who claim it flies in the face of international obligations to protect the great white shark.

Ashen earth strewn with the limbs of once-mighty trees is all that is left of the fearsome forest in central Myanmar that Wa Tote remembers from her youth.

"We would only dare enter in a big group. The forest was deep and had many wild animals. Now we cannot even find a tree's shadow to shelter under when we are tired," the 72-year-old told Agence France Presse.

Small, furry marsupials such as the bandicoot, quoll and tree possums are in dramatic decline in Australia's north and feral cats could be the cause, according to analysis reported Wednesday.

Chris Johnson, a wildlife conservation professor from the University of Tasmania, said small mammal species were at risk of extinction across the continent, but the changes in the north were marked.

When it came time to deliver a new federal report detailing what global warming is doing to America and the dire forecast for the future, President Barack Obama turned to the pros who regularly deliver the bad news about wild weather: TV meteorologists.

"We want to emphasize to the public, this is not some distant problem of the future. This is a problem that is affecting Americans right now," Obama told "Today" show weathercaster Al Roker. "Whether it means increased flooding, greater vulnerability to drought, more severe wildfires — all these things are having an impact on Americans as we speak."

The Obama administration is more certain than ever that global warming is changing Americans' daily lives and will worsen — conclusions that scientists will detail in a massive federal report to be released Tuesday.

Once people thought global warming was more in the future and more of an issue in other parts of the world, but the National Climate Assessment will emphasize how the United States is already paying the multibillion-dollar price for man-made climate change, said study co-author Donald Wuebbles, a climate scientist at the University of Illinois.

A new kind of bird flu has been detected for the first time in Adelie penguins in Antarctica, though the virus does not seem to make them sick, researchers said Tuesday.

The virus is unlike any other avian flu known to science, said the report in mBio, a journal of the American Society for Microbiology.

U.N. chief Ban Ki-moon on Sunday urged "bold" actions by countries around the world to reduce greenhouse emissions and fight global warming.

"I am asking them (world countries) to announce bold commitments and actions that will catalyse the transformative change we need," said Ban at a ministerial meeting in Abu Dhabi to prepare for a September 23 climate change summit in New York.