An international who's who of development and political leaders are meeting today at the U.N. to raise funds for Pakistani flood relief. At the panel's opening session, American and Pakistani officials argued that global climate change is increasing the risk of humanitarian disasters and probably contributed to the scale of the current crisis.

"We should expect to have more large-scale weather events as we see more systematic warming of our planet," said Rajiv Shah, the head of the U.S. Agency for International Development, pointing to what he described as a clear trend of increasing natural calamities tied to climate change. USAID has already responded to 64 natural disasters this year.

Pakistani Foreign Minister Shah Mehmood Qureshi said that the unprecedented size of the flood was due at least in part to warming factors, such as the melting of glaciers in the Himalayas. He said the catastrophe was a perfect storm due to the combination of "exceptionally high rainfall in the north, converging with the monsoons and the glacier melt."

Only after the floodwaters recede will the true extent of the damage become known. Qureshi said. He also defended the Pakistani government's widely criticized relief efforts.

"People have complained that the response hasn't been quick enough, nationally and internationally. Frankly, nobody was expecting to have something like this, at this scale," he said. "Initially there was shock and paralysis. But we are out of it now; we are getting our act together."

"We do need international assistance and we need international assistance now," Qureshi added.

Secretary of State Hillary Clinton is set to announce an increase in U.S. aid for the flood from $90 million to $150 million today. As of yesterday, the U.N. had received less than half of the $450 million needed for immediate relief.

Raymond Offenheiser, the president of Oxfam America, cautioned that vigilance is needed to ensure that countries follow through on the funding that will be promised at today's conference. The Asian Development Bank pledged Thursday morning to grant a $2 billion loan for long term reconstruction.

"It's one thing to pledge the money; it's another thing to deliver it. We've got to keep the pressure on," he said.

Richard Holbrooke, the U.S. special representative for Afghanistan and Pakistan, acknowledged that the international community is competing with militant organizations in the relief effort and that the flood crisis does have strategic implications for the region and for the United States. But that's not what's important right now, he said.

"Obviously we are aware of this. But we are focused solely on helping people in this extreme situation. We will sort out all of the other implications later."

Holbrooke encouraged the audience at the event to text "SWAT" to 50555, which will automatically send $10 to the U.N.'s refugee agency. Donation information for other groups working on the relief effort can be found here.