This Website discusses latest scientific INFORMATION FROM WEBSITES on Science, Nature, Environment, with a focus on Global Warming.
More evidence that global warming is intensifying extreme weather
Get link
Facebook
X
Pinterest
Email
Other Apps
A new study finds that global warming is causing weather whiplash.
An Indian farmer inspects her agricultural field which is badly affected by the heat wave and scanty rainfall in India. Photograph: STR/EPA
Just this week, a new article appeared in the journal Nature that provides more evidence of a connection between extreme weather and global warming. This falls on the heels of last week’s article which made a similar connection. So, what is new with the second paper? A lot.
Extreme weather can be exacerbated by global warming either because the currents of atmosphere and oceans change, or it can be exacerbated through thermodynamics (the interaction of heat, energy, moisture, etc.). Last week’s study dealt with just the thermodynamics. This week’s study presents a method to deal with both.
The authors, Daniel Horton, Noah Diffenbaugh and colleagues used a new technique to tease apart the complex influences of warming on changes to atmospheric circulation. Dr. Horton told me,
Our study focuses on the need to understand the underlying physical causes of extreme weather events, and to systematically test whether the probability of those underlying conditions has changed in recent decades. Events that are so extreme that they fall outside of our historical experience often result from a suite of complex interacting factors. To better understand these factors we’ve developed a method that allows us to partition the climate influences.
Lead author Daniel Horton.
In particular, the authors focused on pressure levels up into the atmosphere (heights of approximately 5 km) from 1979 onwards. Those patterns gave information about atmospheric circulation. The authors grouped the patterns, using seven geographical regions (Europe, Western Asia, Central Asia, Eastern Asia, Western North America, Central North America, and Eastern North America) and four different periods of the year (winter, spring, summer and fall).
They separated changes in circulation from changes in thermodynamic effects. What they found is that most regions have seen increases in summertime warm temperatures in the past three decades. Furthermore, they found that in some regions, a large part of this trend is due to the increases in anticyclonic circulation and atmospheric blocking. The blocking that has been associated with extreme swings of weather (bringing very warm weather to the Western USA and simultaneous cold weather to the east for instance).
The authors show that as the Earth warms, we expect fewer cold temperature events generally. But, in some cases the circulation changes has led to extreme cold outbreaks in some regions. What has happened is that the arctic front, which typically confines cold weather to the Arctic region, has undulated sufficiently to allow cold-air breakouts to the south. Think of the polar vortex from last year.
These findings support the commonly-heard term that has emerged in the past few years of “weather whiplash - wild swings from one extreme to another. Importantly, the authors show that the trends are “statistically significant” and are unlikely just random occurrences.
Noah Diffenbaugh.
That said, the authors clarify,
The majority of the observed changes in extreme temperature occurrence have resulted from changes in the heat content of the climate system. However, we also find that the risk of extreme temperatures over some regions has been altered by changes in the motion of the atmosphere via changes in the frequency and duration of regional circulation patterns.
It’s important to note that the authors do not explicitly attribute the trends to human causes or natural causes. The authors state clearly that we need a deeper understanding of the causes of the trends they’ve found. In particular, a future step will be to separate human-causes from natural variability in the climate on the decadal scale. At the same time, they write,
our quantitative partitioning, in conjunction with targeted climate model simulations offers the potential to fingerprint dynamic and thermodynamic influences in isolation, which in turn may facilitate attribution of the observed trends and projection of future trends.
And that is really what we want to know. How much of this is from humans? How much is natural? And how will things change into the future?
Silent Sea We were the first that ever burst Into that silent sea - ST Coleridge Another vessel sheds the chrome of its silver mile until a mile meanders into three, triples again over the reef. Nothing can breathe under oil, nor register that dark membrane’s slick over sight. We were the first cracking the hull of the earth open, our foolish husbandry a metallurgy that’s brimmed with false gold too often we can talk, and talk, and talk but a ship in space, manned by non-thinking from non-feeling, says absolutely nothing at all. The Body Politic As if history tells itself this way - my country not what it was, my city relatively at ease with its decay. What of the marks on our bodies, coded indices of war? Every movement burns with enough friction to disturb the border between one place and another, to ignite unnerved armies. Who will bear this pain with us? It is not mine, not yours. One day we’ll finish cleaning the dust from the feathers of nightingales. ...
There’s a groundswell of support for climate action leading up to the 2015 Paris talks A museum employee looks at a Dodo in display at The Natural History Museum. Those in denial about climate change have much in common with the dodo. Photograph: Peter Macdiarmid/Getty Images At the end of this year there will be a critically important international climate change conference in Paris . At this conference, nations will attempt to reach an agreement to reduce greenhouse gas emissions and slow global warming. Over the past few months there’s been a flood of big climate-related news, most of which will help build support and pressure for a strong agreement to curb global warming at the Paris conference. The political and social climate is shifting, and those in denial about human-caused climate change are struggling to adapt. Scientific research underscores climate risks John Abraham recently reported on two separate studies published in Nature ...
Global temperature change observed over the last hundred years or so is well within the natural variability of the last 8,000 years, according to a new paper by a former Intergovernmental Panel On Climate Change (IPCC) lead author. Dr. Philip Lloyd, a South Africa-based physicist and climate researcher, examined ice core-based temperature data going back 8,000 years to gain perspective on the magnitude of global temperature changes over the 20th Century. What Lloyd found was that the standard deviation of the temperature over the last 8,000 years was about 0.98 degrees Celsius– higher than the 0.85 degrees climate scientists say the world has warmed over the last century. “This suggests that while some portion of the temperature change observed in the 20th century was probably caused by greenhouse gases, there is a strong likelihood that the major portion was due to natural variations,” Lloyd wrote in his study. The United Nations’ IPCC claims there’s b...
Comments