Addressing the German Bundestag a week before a key summit of EU leaders in Brussels, Angela Merkel said that the European Union was at crossroads and needed to adapt to the challenges of the 21st century.

Focusing on the environment, Merkel said that Germany and Europe could not resolve the climate issue alone.

"I know that we only emit 15 percent of the world's CO2 emissions here in Europe," Merkel said. "And that's why it's obvious that Europe alone cannot solve the climate problem."

Merkel said it was time to act and urged government leaders to follow the recommendations of the European Commission, which has called for a 20-percent reduction in CO2 emissions by the year 2020.

She said the 27-member bloc needed to invest more in new technologies to reduce greenhouse gas emissions to combat the effects of climate change and emphasized that this was an opportunity to demonstrate leadership.

"When we in Europe can show that economics and ecology are compatible, then we will have demonstrated that we can combine technological leadership and innovation with our responsibility toward the rest of the world," she said.

Reviving the constitution

Merkel told parliament that Germany planned to present a road map on how to proceed with the stalled EU constitution when its presidency of the European Union expires at the end of June.

Eighteen of the 27 EU members have ratified the constitution, which French and Dutch voters rejected in 2005. Some countries, notably Britain, have strong reservations about the constitution.

"Europe is our future," she said, adding that problems such as environmental protection, illegal immigration, global trade and international security cannot be resolved by individual states.

Achievements and goals

Merkel said that a summit in the German capital, which will take place in the last week of March to mark the 50th anniversary of the bloc's founding, would result in a Berlin Declaration, setting out past achievements and naming goals for the future.

The German chancellor also vowed to push ahead with efforts to get a deal on world trade this year, saying that an agreement was urgent.

"It is a priority for us to successfully reach a conclusion in the Doha cycle and we are strongly committed to this," Merkel said. "We are aware that the European Union, and Germany, the world's biggest exporter, can benefit from this."

The WTO negotiations, launched more than five years ago to boost commerce and reduce poverty were revived last month after being suspended last year, but there has been little visible progress so far.