A record number of Americans say they accept that global warming is happening, according to a new study by Yale's Climate Communication Communication Program and George Mason's University Climate Communications Communication Center, and nearly three-quarters of them say, that this is a problem that is personally important to them. Both numbers have risen sharply over the last few years – a change that could not be achieved soon enough, as remote critical points and worst climate scenarios that researchers have been predicting for decades have come true.
This week, for example, researchers warned that Greenland's ice sheet has reached a critical point. If we look at more than a decade of ice loss, an international team of scientists found that the rate of ice loss in Greenland in early 2013 was four times higher than in 2003.
Not the fact that the loss of ice accelerated was surprising, but rather where it came from. There are two sources of ice loss in Greenland, according to Michael Bevis, a professor at the University of Ohio and lead author of the new study: pieces of glaciers that fall directly into the ocean and a meltdown, ice onshore. Climate scientists have known that the glaciers of the Arctic people have settled in the sea at an accelerated rate as the ocean around the island is warming, but its ice layer is relatively insulated from rising air temperatures, says Bevis.
Thus, in this new study, Beavis and his colleagues were surprised to see that most of the ice loss occurred in the southwest corner of Greenland, a region with very few glaciers. In other words, most of the ice loss is in the form of a melt drain, draining from the ice layers in the sea.
"We can see an enormous acceleration of ice loss due to melting: Greenland is losing 100 billion tons a year in 2003 and losing nearly 400 billion tons a year at the beginning of 2013," said Bevis. "Then, in the summer of 2013, it just stopped, it was amazing."
What Bevis and his colleagues have found out is that melting is controlled by something called North Atlantic oscillation – uneven fluctuations in atmospheric pressure across the Atlantic Ocean that affect the weather on several continents. NAO has two phases: a negative phase that imports warm air into Greenland and a positive phase that leads to low temperatures. NAO has existed for thousands of years, with little influence on the melting of ice in Greenland. What has changed, says Bevis, is our atmosphere.
"Global warming has led to temperature temperatures in the summer just because of the critical temperature at which massive melting will happen and NAO pushed him above this critical threshold," he says. When NAO went back to the positive phase and the colder air returned, the main melt stopped. That may sound like good news – that a positive NAO can buffer Greenland's ice sheet from global warming – but that's certainly not, says Bevis. This means that the ice sheet is now sensitive to small fluctuations in summer temperatures and if global temperatures continue to rise as expected, Greenland's summer will be warm enough to cause massive melting despite the NAO phase.
Researchers were already concerned about Greenland's contribution to rising sea levels when it is just throwing out icebergs that will slowly melt in the ocean. But Italian water, albeit a source of sea level rise, is also worrying for other reasons. The long-term concern, says Bevis, is that perhaps in 50 or 100 years, "if you put enough fresh water in the oceans near Greenland, you can start violating the world's ocean circulation system."
"It's a 900-pound gorilla on the air conditioning system," says Bevis. "In principle, the climate system exists to dissipate heat, so much of this heat exchange is carried out by global ocean circulation systems." Hot water flows, like the Gulf Stream, carry warm water from the equator to the poles; when hot water arrives around Greenland, it sinks. "If there's a whole bunch of fresh water, he will not want to sink, and the heat conveyer will slow down," Bevis says. "It's hard to say what the consequences will be, but they will be big."
But here's something about these long-term concerns about climate change: So far, they tend to arrive much earlier than expected.
Earlier this month, researchers reported in the journal science that the oceans are warming about 40 percent faster than the UN climate change panel just a few years ago. Last year, a climatologist – he said guardian The Antarctic ice layer now melts with a "surprising" and accelerating level. Bevis has agreed that the last few years have produced "a whole series of documents that say the impact of global warming is underestimated and they are happening faster than expected."
While melting ice sheets and rising sea levels attract much attention, Michael Mann, a climatologist at Penn State University, points out that climate change already has dramatic consequences for extreme weather events in the summer. IN Scientific Achievements An article in October, Mann and colleagues identified a key mechanism by which climate change affects the extreme weather phenomena that the current climate models failed to capture: poor reactor flow. The team found that climate change is the reason once the winding streaming stream remains in place, capturing systems with high or low atmospheric pressure that led to severe heat waves, droughts, forest fires and floods in the US in the summer of 2018 and abroad.
In other words, "wrote Mann in an e-mail," climate models may have underestimated the impact that climate change already has on extreme weather phenomena such as the devastating events that developed in [the summer of] 2018, and they probably underestimate future increases in these events.
Despite this sobering evidence and the increasing recognition of the problem by the public, the current federal administration continues to fight climate change by introducing policies that weaken environmental protection, strengthen fossil fuels and ultimately slow international progress towards the goals of The Paris Agreement. In fact, Tramp officials are trying to discredit some of the toughest climatic sciences – the National Climate Assessment, which is based on the work of more than a dozen federal agencies – as "alarmist" or "radical". White House spokeswoman Sarah Huckyby Sanders argues falsely that the assessment is based only on the "most extreme" scenario of emissions.
"Trumps and fossil fuel lobbies and advocates who run its administration have done their best to deny science, bury government reports that warn of impacts, and abolish previous policies aimed at limiting carbon emissions and stabilizing warming at dangerous levels "wrote Mann. "In this sense – say, from a political point of view, yes – we are witnessing the worst case scenario."
In fact, it is becoming increasingly clear that without immediate and drastic action, the worst climate scenario will become the rule, not the exception.
"We are in a situation where there will be quite serious consequences for what we have done to the atmosphere," said Bevis, "but the longer we slow down, the worse the consequences will be."