28 August 2017, Climate Home, Link between Hurricane Harvey and climate change is unclear. Reports the devastating storm was made worse by humanity’s carbon emissions fail to grasp climate change is not just about warming. The unprecedented amount of rainfall accompanying Hurricane Harvey immediately raised the question whether and to what extent climate change is to blame. In a warming world the vapour capacity of the atmosphere increases, and more extreme rainfall, like Texas is witnessing right now, is to be expected as a result. This leads many to conclude that climate change exacerbated the impacts of hurricane Harvey. It is very appropriate to highlight that this is the kind of event we expect to see more of in a warming world. However, to apply this argument directly and attribute (and quantify) the impacts from Harvey itself to human-induced climate change, neglects that climate change is not just about warming. In a changing climate, two effects come together: not only does the atmosphere warm up (thermodynamic effect) but the atmospheric circulation, which determine where, when, and how weather systems develop, can change as well (dynamic effect). Changes in the atmospheric circulation can increase the thermodynamic effect (as we saw during floods Louisiana in 2016) or act in the opposite direction to the thermodynamic effect, leading to locally decreasing the risk of extreme rainfall or canceling the effect of the warming alone (examples here). Dynamical factors and thermodynamic aspects of climate change can interact in complex ways and there are many examples where the circulation is as important as the thermodynamics. Read More here
Category Archives: Impacts Observed & Projected
24 August 2017, DESMOG, Retired General: ‘Our Bases and Stations on the Coast Are Going Underwater’. This past July, in a Congressional hearing on “The Status and Outlook for U.S. and North American Energy and Resource Security,” retired Marine Brigadier General Stephen A. Cheney offered a dire warning for many current military bases in coastal locations.“From the tactical side our bases and stations on the coast are going underwater. Norfolk [in Virginia] is the prime example. It’s closed dozens of times a year now because of flooding both from rain and sea level rise,” Cheney explained. “We’re going to have to talk about relocation of our bases and stations that are on the coast.” Cheney also made it clear that he believes in climate change.“Climate change is already affecting security both at home and around the world, so we must make sure that we take the greenhouse gas emissions from energy into account, lest we trade increased energy security today for a warmer, more unstable world in the future.” General Cheney certainly isn’t the first to warn of the security implications of climate change. Trump’s Secretary of Defense James Mattis admitted as much in written testimony to Democratic Senators, writing, “Climate change is impacting stability in areas of the world where our troops are operating today.” An article in Navy Times last year noted that 128 military bases are at risk from sea level rise. Sea level rise and coastal flooding represent a well-documented threat to national security. Yet less than a month after General Cheney’s testimony in Congress, the Trump administration rolled back an Obama-era regulation designed to “improve the resilience of communities and federal assets against the impacts of flooding.” Rafael Lemaitre was the the public affairs director for the Federal Emergency Management Agency (FEMA) in the Obama administration and criticized this latest regulatory rollback in comments to The Hill. “Eliminating this requirement is self-defeating,” Lemaitre said. “We can either build smarter now, or put taxpayers on the hook to pay exponentially more when it floods. And it will.” Read More here
21 August 2017, The Conversation, Dry winter primes Sydney Basin for early start of bushfire season. It might feel like the depths of winter, but Australian fire services are preparing for an early start to the bushfire season. Sydney has been covered with smoke from hazard reduction burns, and the New South Wales Rural Fire Service has forecast a “horrific” season. Predicting the severity of a bushfire season isn’t easy, and – much like the near-annual announcements of the “worst flu season on record” – repeated warnings can diminish their urgency. However, new modelling that combines Bureau of Meteorology data with NASA satellite imaging has found that record-setting July warmth and low rainfall have created conditions very similar to 2013, when highly destructive bushfires burned across NSW and Victoria. Crucially, this research has found we’re approaching a crucial dryness threshold, past which fires are historically far more dangerous.How to measure bushfire fuel On September 10, 2013 several bushfires in Sydney’s West caused havoc well before the official start of the bushfire season. These were a precursor to fires that destroyed more than 200 properties a month later. Warm, dry winter weather had dried out the fuels in Sydney’s forests and bush reserves beyond “normal” levels for the time of year. The timing and severity of those preseason fires were a reminder that the region’s forests are flammable all year round; they can burn whenever the fuel they contain dries out past a certain threshold. Read More here
14 August 2017, ECOS, Mapping fire-prone areas before the fires. Two months after Portugal’s deadliest fire season in recent record, thousands of firefighters have again been deployed in the last few days to battle new wildfires. It’s a crisis Australia knows well from its own bushfire history which paints an equally bleak and devastating picture. Events such as Ash Wednesday in Victoria and South Australia in the 1980s, Black Saturday in Victoria in 2009 and the enduring 2001 Black Christmas in NSW, resulted in hundreds of lives lost and close to 5,000 homes destroyed. These are just three examples of a long list of major Australian bushfire events. As we head towards 2050, climate change is predicted to cause fire seasons to start earlier, end later and involve more frequent extremes of weather that support major loss events. More than ever before, planning and preparation is playing a significant role in mitigating major bushfires and their effects on lives, properties and infrastructure. Following a state-wide project that saw CSIRO develop mapping technology that identified bushfire prone areas in Queensland down to a 25 metre square area, our researchers have now stepped onto the international stage by mapping regions all over the world that have conditions susceptible to fire events. This latest global tool is a valuable resource for hazard analysts, financers, developers and even the general public, seeking bushfire information online. Read More here