"Now we can get to work!" she said. "All the big parties have engaged."
"The talks didn't fail. ... I'm going away from COP 15 [the climate summit] a pretty happy camper," University of Texas at Austin ecologist Camille Parmesan wrote in an informal email to some friends and journalists.
Parmesan is widely respected for her work on assessing the impacts of human-induced global warming on ecosystems around the world.
"I didn't expect a treaty from this -- don't know why anyone would have. Isn't this the first time in many years that both the USA and China are here to seriously participate?" Parmesan wrote. "What I had hoped was that serious talks could begin, and that there would be a general feeling that agreement on details could be reached over the next years, and pretty much that's what happened."
"I was thrilled to hear that Obama had a one-on-one with the Chinese Premier," she wrote. "We can't have global agreement on such an important and highly charged issue until the Heads themselves can sit face to face and talk frankly... It's the true beginning of the road to a treaty."
While some leading American climate scientists clearly now feel elation after so many years trying to warn the world about the dangers of unchecked climate change, these hopes are nonetheless counterbalanced by plenty of awareness -- and more worried warnings from other scientists -- about the inadequacies of the Copenhagen Accord, to say nothing of the fact that it is entirely non-binding, and was, officially, simply "noted" by the Conference of the Parties to the U.N. Framework Convention on Climate Change.
Leading climatologist Richard Somerville, professor emeritus at Scripps Institution of Oceanography in San Diego, told ABC News that "Mother Nature imposes a timescale on when emissions need to peak and then begin to decline" if highly dangerous warming is to be avoided.
"This urgency is not ideological or political, but rather is due to the physics and biogeochemistry of the climate system itself," he said.
He directed our attention to what he calls his "ski-slope graph" (on page 51, figure 22) in the new Copenhagen Diagnosis report.
Somerville and 25 other leading scientists from eight countries published the report, which can be found here, just before the Copenhagen summit as an update, based on more than 200 peer-reviewed studies, to the science on the most recent report of the U.N.'s Intergovernmental Panel on Climate Change, which is now three years old and outmoded in some important ways, especially regarding the acceleration of sea level rise.
This graph depicts three different scenarios for drastic emissions cuts that must be taken worldwide if the average global temperature is to be kept below 2 degrees Celsius above pre-industrial averages.
"Even if everything promised in the new Copenhagen Accord were successfully executed, it would still cap the temperature rise at about 3 degrees, at best, not 2," he said.
And then he added: "Mother Nature bats last."