Posts Tagged ‘climate change’
By Nell Greenfieldboyce (NPR) July 11, 2016
The way clouds cover the Earth may be changing because of global warming, according to a study published Monday that used satellite data to track cloud patterns across about two decades, starting in the 1980s.
Clouds in the mid-latitudes shifted toward the poles during that period, as the subtropical dry zones expanded and the highest cloud-tops got higher.
These changes are predicted by most climate models of global warming, even though those models disagree on a lot of other things related to clouds, says Joel Norris, a climate scientist at the University of California, San Diego.
“I guess what was surprising is that a lot of times we think of climate change as something that’s going to occur in the future,” says Norris. “This is happening right now. It’s happened during my lifetime — it was a bit startling.”
About 70 percent of our planet is covered by clouds, at any given moment. These constantly moving shape-shifters aren’t exactly easy for scientists to study.
Clouds aren’t as simple as their fluffy nature might suggest. To understand them, scientists have to track the behavior of tiny water droplets, as well as huge masses of clouds that might be hundreds of miles wide.
And climate modelers also have to take into account the fact that clouds can have two different effects on temperatures.
“During daytime, if there are a lot of clouds present, thick clouds, then that will keep the temperature cooler,” says Norris, because clouds reflect incoming sunlight back to space.
But thick clouds can also act like a blanket that keeps the Earth’s warmth in, he says, “which is the reason why a cloudy night won’t be as cold at the surface as a clear night.”
Clouds have been called the wild card of climate science. Researchers argue over how exactly global warming will affect clouds and vice versa.
While weather satellites can give you tons of cloud pictures, Norris says these satellites aren’t that great for trying to figure out long-term trends.
“The difficulties we have is that every few years a new satellite is put up with a different instrument, the orbits change, and this all changes how much cloud the satellite measures,” Norris explains.
So he and his colleagues recently did a bunch of corrections that would make it possible to compare cloud measurements over a couple of decades, starting in the 1980s.
In this week’s issue of the journal Nature, the researchers explain how their findings match what scientists would expect to see, based on climate models.
Norris says it’s probably happening primarily because of two influences — human-produced global warming, and also the recovery from the cooling effect of two volcanic eruptions during that time frame.
So will other climate researchers buy this new history of clouds? Kevin Trenberth at the National Center for Atmospheric Research in Colorado isn’t so sure.
“This is a very good attempt to try and get a handle on this, but I don’t think it’s the final answer,” says Trenberth, who notes that the time frame studied was pretty short and included a period often described as the global warming hiatus, from 1999 to 2013.
Climate researchers still have a lot of work to do when it comes to understanding clouds, says Trenberth, who believes the state of the science is still like that old Joni Mitchell song Both Sides Now, in which she sings, “I really don’t know clouds at all.”
by AMNH on
A series of papers recently published by scientists at the American Museum of Natural History suggests that polar bears in the warming Arctic are turning to alternate food sources. As Arctic sea ice melts earlier and freezes later each year, polar bears have a limited amount of time to hunt their historically preferred prey—ringed seal pups—and must spend more time on land.
The new research indicates that at least some polar bears in the western Hudson Bay population are using flexible foraging strategies while on land, such as prey-switching and eating a mixed diet of plants and animals, as they survive in their rapidly changing environment.
“There is little doubt that polar bears are very susceptible as global climate change continues to drastically alter the landscape of the northern polar regions,” said Robert Rockwell,a research associate in the Museum’s Department of Ornithology. “But we’re finding that they might be more resilient than is commonly thought.”
Polar bears are listed as a threatened species under the United States Endangered Species Act and are classified as “vulnerable” with declining populations on the International Union for Conservation of Nature and Natural Resources’ Red List. Climate warming is reducing the availability of their ice habitat, especially in the spring when polar bears gain most of their annual fat reserves by consuming seal pups before coming ashore for the summer. The new work, led by Rockwell and Linda Gormezano, a postdoctoral researcher in the Museum’sDivision of Vertebrate Zoology, examines how polar bears might compensate for energy deficits from decreasing seal-hunting opportunities.
In the first paper, published in spring 2013 in the journal Polar Ecology, the researchers provide, for the first time, data and video of polar bears pursuing, catching, and eating adult and juvenile lesser snow geese during mid-to-late summer, when the geese are replacing their primary flight feathers.
In the second paper, published in summer 2013 in the journalEcology and Evolution, researchers used polar bear scat to show that the diet of at least some of the bears has shifted from what it was 40 years ago, before climate change was affecting the Hudson Bay lowlands. Today’s polar bears are preying more on caribou as well as on snow geese and their eggs.
In the final paper in the series, published in December 2013 in the journal BMC Ecology, the researchers show that polar bears are, with a few exceptions, consuming a mixed diet of plants and animals. The predominance of local vegetation in collected scat suggests little movement among habitat types between feeding sessions, indicating that the polar bears are keeping energy expenditure down.
Taken together, the research indicates that during the ice-free period, polar bears are exhibiting flexible foraging behavior. This behavior likely derives from a shared genetic heritage with brown bears, from which polar bears separated about 600,000 years ago.
For more details, see the Museum’s press release.
(NOTE to readers) Be sure to see the Pickles cartoon at the end of this editorial.
Global warming of the earth’s atmosphere has been attributed to increases in the emissions of greenhouse gases into the atmosphere, especially carbon dioxide emissions that have resulted from the burning of fossil fuels. Land use activities, such as tropical deforestation (such forests were once referred to as the “lungs of the earth”) are also contributing to the amount of CO2 that stays in the atmosphere.
Global warming and tropical deforestation are “creeping” environmental changes, where today’s CO2 levels are like yesterday’s and tomorrow’s levels will be like today’s. Like the frog in the boiling water analogy, there is no hard and fast indicator for when a dangerous threshold has been crossed with regard to greenhouse gas levels, but once it has been crossed, major irreversible adverse changes are expected to occur. At that point major environmental troubles for society become visible and, with the benefits of hindsight, become attributable to a major change in the earth’s climate. For example, though scientists tell us there will be more extremes, it is hard to see that from day to day. Even under ‘normal’ climate conditions, one must keep in mind that record-breaking climate and weather events are occurring somewhere on the globe every year.
It appears that NO GOVERNMENT DEALS WELL IN ADVANCE OF A CREEPING ENVIRONMENTAL CHANGE, UNTIL A CRISIS HAS EMERGED BUT BY THEN IT IS TOO LATE IN THE DAY TO RESPOND EFFECTIVELY. As a result, societies end up having to cope with an environmental crisis situation that is often more deadly, more destructive and more costly than if they had dealt with the less threatening seemingly harmless incremental changes from year to year or decade to decade.
Governments, the big ones especially, are backing up into the future. How to turn them around to look into the future is the challenge that has faced older generations alive today. Despite new technological breakthroughs, trying to get governments to figure out why or how to cope with slow onset, incremental but accumulating adverse environmental changes is an almost impossible task. As I proposed at the Nepal Small Earth Network-CCB conference <www.smallearth.org.np/>, we need to come up with a “Plot to Save the Planet”… and very soon. It seems that developing that plot will be up to the youth to develop, not the climate change negotiators who have become mired in detail (e.g., “not seeing the forest because the trees are in the way”).
I have come to realize, following the conference in Nepal and the first few days at UN COP16 <see earlier editorials here>, that we have to re-think the concept of “youth”. It has different connotations to different people. Teens are youth to other people. People still in a university are considered youth by still others. To many, the young are small, child-like, harmless humans who are seldom listened to until they become adults: but, is that how young people want to be viewed regardless of age?
I suggest that there be a decade-wise view of humans where youth are up to the teens (high school and early college years) and succeeding categories are to be branded as “20somethings”, the “ 30-somethings”, the “40-somethings”, and so forth. One could argue that each of these age groups (age cohorts) are generally speaking more like each other in terms of knowledge, goals, enthusiasms, shared lived history, etc. than they are with their neighboring age groups. The lines separating the adjacent age groups are not sharply defined so there is some flexible overlap.
The above suggestion means that I am … gasp … among the 70-somethings, the age group with lots of information and experience but with rapidly waning power to influence! The 20-somethings (with a degree of overlap with “youth”) are in the process of gaining knowledge, training and experience. They hold the keys to safeguarding the future. They are young adults (although it is often used, I do not like this term as it labels them with a junior status) preparing to take on the world. They are no longer youth, playing in a sand box or youth in middle school, ignored for their thoughts. They are out in the real world. They are increasingly demanding to be listened to and still unencumbered by bureaucratic rules and regulations. So, youth, the 20-somethings, the 30-somethings, the 40-somethings, and so on, of the world unite and challenge those professing to want to save the planet’s atmosphere but whose activities do not support their words.
As for those age groups in front of yours, hold them accountable for their “damnages” to the planet. [NB: “damnages” is damage that a decision maker knows will occur (and does occur), as a result of his/her decision or indecision].
As a final point on this, I would also argue that the 20-somethings and the 70-somethings make the best allies, as the former gain the tools that they need to bargain while the latter have the experiences that can be used to mentor and guide them without expectation of personal gain.
The day I wrote the first draft of this editorial I noted in my local newspaper the following cartoon called Pickles (free at http://comics.com/pickles/). It underscored the need for making explicit the possible contributions, at least in terms of mentoring, that older generations alive today can provide face to face to the younger generations.
April 14/15 2010
“You can call me a ‘good skeptic.’ I don’t buy everything the [climate] modelers say. I don’t buy everything the climate people say. I’ve worked with them for 40 years. I know where some of the Achilles heels are; some of the arguments,” states Dr. Mickey Glantz, the Director of the Consortium for Capacity Building, University of Colorado.
“However, I do see sea level rising. I do see the ten warmest years on record in recent times. Warm ecosystems moving up-slope, that worries me,” as do other confirmed climate change observations, which he recounts in this candid assessment of the realities of climate change and what , if anything, mankind can do about. But while Glantz recognizes the problems of forecasting the long-range impacts of climate change, for him an equally challenging issue is getting us to agree there is a problem. He asks friends and colleagues, What would it take to get you to change your views on climate change? No one can offer an answer.
He recommends moving aside the climate scientists and IPCC and convening a engineering panel to start addressing the practical aspects of how to tackle the problem, noting that ‘there is no Planet B.’
Other video presentations from the 2010 Toyota Sustainable Mobility Seminar are available on EV World.Com.