Leaders warn of grave climate consequences on first day of talks

Choose hope over surrender in the fight against climate change--

That's the call from U.N. Secretary General Antonio Guterres as the COP25 climate summit began in Madrid on Monday (December 2).

Two weeks of talks aimed at bolstering the 2015 Paris Agreement to curb global warming began against a backdrop of unusually severe weather disasters this year,

from fires in the Arctic, Amazon and Australia to intense tropical hurricanes.

Guterres, a leading climate advocate, urged governments to lead the way.

(SOUNDBITE)(English) UNITED NATIONS SECRETARY GENERAL, ANTONIO GUTERRES, SAYING:

"And so my strong appeal to political leaders here today, is please do lead, and do not follow because societies are moving, business communities are moving, local authorities are moving, the youth are moving. It is for political leaders to be able to take profit of these movements and to lead, for us to be able to defeat climate change."

It was a message echoed by the speaker of the U.S. House of Representatives Nancy Pelosi,

who pledged the country's commitment to the cause.

(SOUNDBITE)(English) U.S. HOUSE OF REPRESENTATIVES SPEAKER, NANCY PELOSI, SAYING:

"For future generations. This is a mission, this is a passion, this is a scientifically based approach, to all. We are here to say to you, on behalf of the House of Representatives to the Congress of the United States, we are still in it. We are still in it."

Scientists say the existing pledges made under the Paris accord fall far short of the kind of action needed to avert the most disastrous consequences of global warming.

Delegates are hoping to use the summit-- which wraps up on December 13-- to inject fresh momentum into the process