13 July 2017, Climate Central, Greenhouse Gases Are Rapidly Changing the Atmosphere. Humanity’s grand experiment in the atmosphere continues, and a new report documents just how far it’s gone. On Tuesday, the National Oceanic and Atmospheric Administration released its annual index of 20 key greenhouse gases. It shows that their direct influence on the climate has risen 140 percent since 1750, with 40 percent of that rise coming in just the past 26 years. That increase is almost entirely due to human activities and has caused the planet to warm 1.8°F (1°C) above pre-industrial temperatures. The index takes greenhouse gas measurements from about 80 ships and observatories around the world — gathered in all their parts per million and parts per billion glory — and boils them down into a simple numerical index, which defines the rise from 1700-1990 as 100 percent or simply 1. This year’s number: 1.4. It’s a simple number that contains multitudes. For example, carbon dioxide’s influence on the climate has increased 54 percent overall since 1990. The four other major greenhouse gases in the index, which include nitrous oxide, methane and two types of chlorofluorocarbons, are responsible for 42 percent of the increase with 15 minor greenhouse gases accounting for the missing 4 percent. Carbon dioxide has risen rapidly in the atmosphere, with 2016 marking the second-largest annual increase ever observed at the Mauna Loa Observatory, the world’s main measuring station. This May, monthly carbon dioxide peaked at 409.65 parts per million. That’s a record high and a mark unseen in human history. If emissions continue on their current trend, the atmosphere will hit a state unseen in 50 million years. A bright spot in the report is the decline of chlorofluorocarbons’ warming influence on the planet. The chemicals were commonly used as refrigerants until the Montreal Protocol banned them in 1989. The treaty came about because they deplete the protective ozone layer, but phasing them out has also helped reduce their warming impact on the climate. Read More here
Category Archives: Impacts Observed & Projected
6 July 2017, The Guardian, Hopes of mild climate change dashed by new research. Planet could heat up far more than hoped as new work shows temperature rises measured over recent decades don’t fully reflect global warming already in the pipeline. Hopes that the world’s huge carbon emissions might not drive temperatures up to dangerous levels have been dashed by new research. The work shows that temperature rises measured over recent decades do not fully reflect the global warming already in the pipeline and that the ultimate heating of the planet could be even worse than feared. How much global temperatures rise for a certain level of carbon emissions is called climate sensitivity and is seen as the single most important measure of climate change. Computer models have long indicated a high level of sensitivity, up to 4.5C for a doubling of CO2 in the atmosphere. However in recent years estimates of climate sensitivity based on historical temperature records from the past century or so have suggested the response might be no more than 3C. This would mean the planet could be kept safe with lower cuts in emissions, which are easier to achieve. But the new work, using both models and paleoclimate data from warming periods in the Earth’s past, shows that the historical temperature measurements do not reveal the slow heating of the planet’s oceans that takes place for decades or centuries after CO2 has been added to the atmosphere. “The hope was that climate sensitivity was lower and the Earth is not going to warm as much,” said Cristian Proistosescu, at Harvard University in the US, who led the new research. “There was this wave of optimism.” The new research, published in the journal Science Advances, has ended that. “The worrisome part is that all the models show there is an amplification of the amount of warming in the future,” he said. The situation might be even worse, as Proistosescu’s work shows climate sensitivity could be as high as 6C. Read More here
28 June 2017, Climate Home, Even Boeing-747 tanker jets can’t win our total war on fires. The more effectively we suppress fires, the worse they become. As climate change makes the world more combustible, we need a new approach. In 1910 Ed Pulaski, a US Forest Service ranger, rounded up his men who were fighting a forest fire in dense conifer forests in northern Idaho and forced them, some at gunpoint, to take refuge in an abandoned mine shaft. The Pulaski tunnel (now a tourist site) represents the dramatic historical moment when ad-hoc approaches to controlling wildfire were shown to be utterly inadequate – this heroic failure provided the impetuous for the US Forest Service to declare total war on fire. Nearly all of Pulaski’s men survived the conflagration, one of thousands of fires that burnt across Idaho during an extremely hot and dry summer, an event now known at the ‘Big Burn’. The sheer ferocity, geographic scale and destructive power of the 1910 Idaho fires shifted the focus of the US Forest Service (USFS) from forestry toward fire fighting. This led to the development of networks of fire towers to identify wildland ignitions. They would be extinguished by teams of trained forest fire fighters, many of whom use a combined ax and mattock invented by, and named after, Ed Pulaski.The iconic mascot Smokey Bear was created by the US advertising industry to promote forest fire awareness. The USFS fire fighting policy evolved to a mandated extinguishment of any new forest fire ignition by 10am the following day, with some managers demanding that the fire size was kept below 10 acres. This total war on fire also drove innovation. In the early 1960 the USFS established Fire Lab at Missoula where an aeronautic engineer, redeployed after the defence department project he was working on was cancelled, developed the first mathematical description of fire, creating the foundation for predictive fire behaviour modelling….But there is a very big catch. The US approach is proving to be ecologically and economically unsustainable – especially in an era of increasing fire threat due to climate change.1 Total fire suppression has created the ‘fire suppression paradox’: the more effective suppression is the worse fires become. Fuel that would historically have been burnt by lightning or indigenous people builds up, resulting in catastrophic fires that are uncontainable regardless of the available technology. The fire suppression paradox also has another unintended and counterproductive consequences: communities come to believe flammable landscapes are safe, resulting in increasing urban sprawl into wildlands that are primed to burn. This massively increases the risk of loss of life and property and the inevitable, tragic loss drives further investment into aerial fire fighting. Climate change is turbo-charging this feedback – fire seasons are worsening, fire disasters are becoming more destructive, and hence demands for more investment in aggressive fire fighting are growing worldwide. Collectively this is creating a dangerous and economically and ecologically unsustainable fire-suppression spiral. Read More here
28 June 2017, The Conversation, The world’s tropical zone is expanding, and Australia should be worried. The Tropics are defined as the area of Earth where the Sun is directly overhead at least once a year — the zone between the Tropics of Cancer and Capricorn. However, tropical climates occur within a larger area about 30 degrees either side of the Equator. Earth’s dry subtropical zones lie adjacent to this broad region. It is here that we find the great warm deserts of the world.Earth’s bulging waistline Earth’s tropical atmosphere is growing in all directions, leading one commentator to cleverly call this Earth’s “bulging waistline”. Since 1979, the planet’s waistline been expanding poleward by 56km to 111km per decade in both hemispheres. Future climate projections suggest this expansion is likely to continue, driven largely by human activities – most notably emissions of greenhouse gases and black carbon, as well as warming in the lower atmosphere and the oceans. If the current rate continues, by 2100 the edge of the new dry subtropical zone would extend from roughly Sydney to Perth. As these dry subtropical zones shift, droughts will worsen and overall less rain will fall in most warm temperate regions. Poleward shifts in the average tracks of tropical and extratropical cyclones are already happening. This is likely to continue as the tropics expand further. As extratropical cyclones move, they shift rain away from temperate regions that historically rely upon winter rainfalls for their agriculture and water security. Researchers have observed that, as climate zones change, animals and plants migrate to keep up. But as biodiversity and ecosystem services are threatened, species that can’t adjust to rapidly changing conditions face extinction. In some biodiversity hotspots – such as the far southwest of Australia – there are no suitable land areas (only oceans) for ecosystems and species to move into to keep pace with warming and drying trends. We are already witnessing an expansion of pests and diseases into regions that were previously climatically unsuitable. This suggests that they will attempt to follow any future poleward shifts in climate zones. Read More here