19 December 2016, Climate News Network, Growing tornado impact puzzles scientists. The US seems to be experiencing more and worse tornado outbreaks – groups of twisters in quick succession. But climate change may not be the culprit. Tornado outbreaks – those sudden, multiple whirlwinds that can randomly destroy whole townships or pass by and do little more than ruffle the prairie grass – may be getting more frequent and more powerful in the United States. And nobody can be sure why. Climate change driven by global warming which is in turn the consequence of greenhouse gas emissions from fossil fuel combustion could be a candidate cause. But meteorologists cannot rule out some other potential explanation, such as some natural cycle in climate behaviour involving oceans and atmosphere. But they do know that tornado outbreaks are becoming potentially more destructive. Two years ago, researchers checked the data and found that the tornado “season” in the US was now two weeks earlier than it had been in the early 20th century. In the spring of 2016 a team from Columbia University checked the records since 1954 and found that the number of individual tornadoes during any single episode of tornado outbreaks has been rising for the past six decades. Worse winds And now Michael Tippett, a physicist at Columbia Engineering, has returned to the challenge. He and two colleagues report in the journal Science that not only are the numbers of twisters in each outbreak growing, but the overall severity of the whirlwinds is on the increase. And the fastest increase is in the most extreme range of the phenomenon. Read More here
Tag Archives: Extreme Events
8 December 2016, Climate Home, Catch 22: when climate change *prevents* migration. Research shows those hit hardest by climate change can’t afford to move, supporting the call for more and better adaptation. Nobody wants to leave home. Even when it gets so hot that your crops fail, or the seasonal flood turns your house into a pond. But for some of the most vulnerable, the option isn’t even there. In Kenya, where about 60 to 80% of the population lives in slums, flooding is a regular menace that disrupts the life of the poor, often making the difference between a small income and an empty plate. Nairobi’s informal settlements cover only 6% of the total residential land area, yet 60% of the 3 million living in the Kenyan capital calls them home. For many slum residents, living in an insecure environment is not a choice and the prospect of climate change worsening the flooding problem fills them with dread. But escaping climate change is not that easy if you are poor. Western leaders, including US president Barack Obama and senior military figures, warn climate change could lead to “mass migration” and a “refugee crisis of unimaginable scale“. If climate change is not addressed urgently, they say, in the near future tens of millions of people will flee from rising sea levels, drought and even conflict exacerbated by harsher environmental conditions. The evidence available to date paints a more complex picture. A recent study examined the trends in six years of migration and weather data from Kenya, Uganda, Nigeria, Burkina Faso and Senegal. “Many people would assume that extreme heat would force households to send more migrants out,” said Clark Gray, lead author of the study. “That’s what’s happening in Uganda but not in other countries.” Read More here
5 December 2016, The Conversation, Can we blame climate change for thunderstorm asthma? Australians have been left unsettled by the recent thunderstorm asthma event that claimed eight lives in Melbourne. As with previous extreme weather events, we are left to wonder whether it was climate change at work, if it will happen again and if it will be worse next time. We can’t say for sure if the thunderstorm asthma event was caused directly by climate change. But modelling each extreme event is neither feasible nor necessary. All weather events should now be considered in the context of climate change and general climate projections are sufficiently alarming to justify the need for governments to prepare for, and adapt to, new risks these pose to our health…..Climate change poses a threat to health directly through extreme weather events, warmer average temperatures and sea level rise. Indirectly it can destabilise the systems that keep our air clean, produce our food, provide us with fresh drinking water and enable economies to thrive. These shifts pose a threat to livelihoods, food and water security, and social and political stability. Read More here
4 December 2016, University of Melbourne – Pursuit, A long climatic affair. The first extensive retrospective of our climate history has traced the human fingerprint on record-breaking hot temperatures as far back as the 1930s. In recent years climate scientists have been examining what role climate change has played in unusual extreme weather events such as Australia’s hottest summer in 2012-13 and recent heatwaves. But before now, no-one had looked at how far back in time we could go and still link weird weather and record-breaking climate extremes to our influence. Our study, published in Geophysical Research Letters, addresses the question of when exactly climate change started altering the influence of record hot years and summers in a way we can detect. We looked at five regions of the world, as well as the whole globe. Human-made climate change has been influencing heat extremes for decades, with many past records directly attributable to the effect we have had on the climate. We found the last 16 record-breaking hot years globally up to 2014 were made more likely because of climate change (we didn’t include 2015 – the current holder of the hottest year record – because we performed our analysis before the end of last year). Read More here