Hungry polar bears gathering along the tundra, twice as many record-breaking temperatures and stronger hurricanes are among the latest signs of climate change, scientists say.
And we can expect more rain, more drought and fiercer storms in the future if the world continues on its fossil-fuel gobbling track, they told reporters on a conference call on Wednesday to discuss the year in global warming.
Michael Mann, a leading US scientist, said he just returned from a trip to Churchill, Manitoba, the Canadian shore town famous for its polar bears, where the sea ice they depend on for hunting seals has not yet formed because of warm temperatures.
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"When you go up there you see the bears all along the coast on the tundra awaiting the sea ice to form and it hasn't formed yet," Mann said.
"This was for me a very tangible and personal opportunity to see the impacts of climate change firsthand," he said. "The Arctic is in many respects a harbinger of things to come on our planet."
Mann also pointed to research being presented on Capitol Hill by another climate scientist, Jerry Meehl of the National Centre for Atmospheric Research (NCAR), showing the number of record-breaking hot days is twice as high as the record cold days.
"Heat records are outpacing cold records at a factor of two to one now. That number is expected to increase to 20 to one by late this century if we continue on the course that we are on with fossil fuel burning," Mann said.
Some events, such as the 2003 European heat wave which killed about 35,000 people and this year's heat wave in Moscow would be "extremely unlikely to happen in the absence of climate change," he added.
Hurricane expert Greg Holland said the fiercest storms are already showing an uptick in frequency, and more powerful hurricanes lie ahead.
"If you just look at the Atlantic in the last 10 years, we have experienced three times as many category 5 hurricanes as have occurred in previous history on a relative basis," he said.
"We now have consensus statements coming out from the scientists and indeed a lot of regional research is pointing all in the same direction. There is nothing going in the other direction," he said.
"And that is the very intense hurricanes, the very intense [category] fours and fives are going to increase and they could be doubling or tripling."
Holland also predicted more rain and drought in the coming years.
"As the earth warms up the atmosphere can hold more water; if there is more water available there will be more rain. Paradoxically of course there is as a result of that more drought because the land dries out quicker."
Mark Serreze, of the National Snow and Ice Data Centre, said the reduction of sea ice in the Arctic would have a growing impact on temperatures in the rest of the world.
"What we have seen is a rather pronounced reduction in the extent of sea ice. At the end of summer now we have 40 per cent less sea ice than we had say during the 1970s," Serreze said.
"We are losing that insulator so what we are seeing now are big fluxes in heat from the ocean to the atmosphere," he said.
"Since everything is connected together in the climate system what happens up there can influence what happens down here and I am talking about in the middle latitudes."
The other thing that the scientists said was changing, along with climate, was how they confront sceptics who question the reality of climate change and the extent of humans' role in causing it.
"There are still many of us who like to sit in our office or go into the field and just do our science and not enter into the fray, but I think that is changing," Serreze said.
"We have to become more involved," he added. "We have to become better communicators. Scientists are not always good communicators of the issues but this is part of a learning curve and we have got to face that."
Mann, a Nobel-Prize winning scientist who was cleared of allegations of misconduct this year stemming from a series of leaked emails between scientists about climate change, said he too had learnt from his experiences.
"One lesson is that if you're a climate scientist and you are willing to play a prominent role in the public discourse on climate change then you'd better have a thick skin," he said.