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: The Science
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
5 July 2017, The Guardian, Climate Change Authority loses last climate scientist. Imagine, if you will, a government board to champion Australian arts without any artists on it, or an agency to advise on medical research without any medical researchers. Or perhaps even, imagine a government authority set up to provide expertise on climate policy without any actual climate scientists. Well you don’t have to imagine that last one, because that’s what we now have – the government’s Climate Change Authority is now sans climate scientist. Prof David Karoly, of the University of Melbourne, has just finished his term on the authority’s board – the only member to stick it out for the full five years. Karoly says without someone to replace him, the authority will struggle to fulfil its legal mandate. He told me: I think that it is critically important that at least one member of the Climate Change Authority is an expert and experienced climate change scientist. Such a member is needed to provide information and interpretation on the latest climate change science publications and data. In my view, it can only do that with a climate change scientist as a member, to provide expert assessment of the effectiveness of proposed greenhouse gas emission reductions nationally and globally, and the projected impacts on Australia from current and future climate change. The Climate Change Authority Act 2011 states that, in conducting a review, the authority must have regard to environmental effectiveness among a number of other matters. I asked the Department of the Environment and Energy if there were any plans to replace Karoly with another climate scientist. The department said: Government appointments to the CCA are a matter for the Government under the CCA’s legislation. The Chief Scientist is an ex officio Member of the Authority and can assist on scientific matters and in providing access to the scientific community, including climate scientists. So in other words, it won’t replace Karoly and will instead just rely on the chief scientist, Alan Finkel, to act as a go-between, which of course is much more efficient and logical than actually having a climate scientist right there in the room. That would be silly, right? 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