16 July 2016, Climate News network, Cyclones set to get fiercer as world warms. New analysis of cyclone data and computer climate modelling indicates that global warming is likely to intensify the destructive power of tropical storms. Powerful tropical storms − known variously as cyclones, typhoons and hurricanes − bring death and destruction to huge swathes of the Earth’s surface. And new research suggests that they are likely to become even stronger. Storms such as the super-typhoon Nepartak that scoured Taiwan earlier this month with winds of 150 miles per hour and then flooded parts of China, are expected to grow even fiercer as the planet warms. That trend is not clear yet, but scientists in the US say it soon will be. Ironically, one of the main reasons why these storms will gain in power is theeffort in many countries to reduce air pollution. Damaging as it is in stunting and shortening lives, the one arguable benefit of filthy air is its ability to dampen the effects of greenhouse gases (GHGs) on cyclones and their like. Over the last century, tiny airborne particles called aerosols, which cool the climate by absorbing and reflecting sunlight, have largely cancelled out the effects of GHG emissions on tropical storm intensity, according to a new scientific review paper published in Science journal. Read More here
Category Archives: Impacts Observed & Projected
11 July 2016, Carbon Brief, Shifting global cloud patterns could amplify warming, study says. A new study sheds light on one of the biggest uncertainties in predicting future changes to Earth’s climate: clouds. Clouds both warm the planet by insulating the Earth’s surface like a blanket, while simultaneously cooling it by reflecting away energy from the sun. Climate models predict that as the Earth warms in response to greenhouse gases, clouds will shift towards the poles and sit higher in the sky, further speeding up warming. But clouds are tricky to measure and until now, scientists haven’t been able to find direct evidence that these changes were actually happening in the real world. The new study published in Nature uses satellite data to identify how cloud patterns have changed in recent decades, confirming the pace of warming predicted by climate models. Satellite data Scientists use weather satellites to measure the extent, height and thickness of clouds. But these measurements suffer from several issues that can limit how useful they are for detecting long-term changes in cloudiness. Small discrepancies in the data are caused by satellite sensors degrading over time and being replaced by new, more precise instruments. Another issue is the gradual change in the orbit of satellites themselves, says the study’s lead author, Prof Joel Norris, professor of climate and atmospheric sciences at the Scripps Institution of Oceanography in San Diego. He explains to Carbon Brief: Read More here
5 July 2016, Washington Post, This new Antarctica study is bad news for climate change doubters. or a number of years now, climate change skeptics have argued that there’s a key part of the Earth’s climate system that upends our expectations about global warming, and that is showing trends that actually cut in the opposite direction. This supposed contrary indicator is the sea ice that rings the Antarctic continent, and that reached a new all-time record extent of 7.78 million square miles in September 2014 (see above). As that record suggests, this vast field of ice has been expanding in recent years, rather than shrinking. That means it’s doing the opposite of what is happening in the Arctic, where sea ice is declining rapidly — and also that it’s doing the opposite of what we might expect in a warming world. [Climate change skeptics may be about to lose one of their favorite arguments] Scientists don’t fully understand why Antarctic sea ice is growing — suggested explanations have posited more glacial melt dumping cold fresh water into the surrounding seas, or the way the Antarctic ozone hole has changed the circulation of winds around the continent. In a new study in Nature Geoscience, though, researchers with the National Center for Atmospheric Research (NCAR) in Boulder, Colo., along with colleagues from the University of Washington in Seattle and Australia, suggest that the phenomenon is simply the result of natural variability of the climate system — driven, in this case, by changes in the tropical Pacific Ocean that reverberate globally. Read more here
30 June 2016, NASA. Why a half-degree temperature rise is a big deal. The Paris Agreement, which delegates from 196 countries hammered out in December 2015, calls for holding the ongoing rise in global average temperature to “well below 2 °C above pre-industrial levels,” while “pursuing efforts to limit the temperature increase to 1.5 °C.” How much difference could that half-degree of wiggle room (or 0.9 degree on the Fahrenheit scale) possibly make in the real world? Quite a bit, it appears. The European Geosciences Union published a study in April 2016 that examined the impact of a 1.5 degree Celsius vs. a 2.0 C temperature increase by the end of the century, given what we know so far about how climate works. It found that the jump from 1.5 to 2 degrees—a third more of an increase—raises the impact by about that same fraction, very roughly, on most of the phenomena the study covered. Heat waves would last around a third longer, rain storms would be about a third more intense, the increase in sea level would be approximately that much higher and the percentage of tropical coral reefs at risk of severe degradation would be roughly that much greater. But in some cases, that extra increase in temperature makes things much more dire. At 1.5 C, the study found that tropical coral reefs stand a chance of adapting and reversing a portion of their die-off in the last half of the century. But at 2 C, the chance of recovery vanishes. Tropical corals are virtually wiped out by the year 2100. Read More here