1 June 2017, The Conversation, Global stocktake shows the 43 greenhouse gases driving global warming. The most comprehensive collection of atmospheric greenhouse gas measurements, published today, confirms the relentless rise in some of the most important greenhouse gases. The data show that today’s aggregate warming effect of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) is higher than at any time over the past 800,000 years, according to ice core records. Building on half a century of atmospheric measurements by the international research community, we compiled and analysed the data as part of a group of international scientists, led by Malte Meinshausen from the University of Melbourne in collaboration with CSIRO. Together, the data provide the most compelling evidence of the unprecedented perturbation of Earth’s atmosphere. They clearly show that the growth of greenhouse gases began with the onset of the industrial era around 1750, took a sharp turn upwards in the 1950s, and still continues today. Research has demonstrated that this observed growth in greenhouse gases is caused by human activities, leading to warming of the climate – and in fact more than the observed warming, because part of the effect is currently masked by atmospheric pollution (aerosols). The new collection of records comes from measurements of current and archived air samples, air trapped in bubbles in ice cores, and firn (compacted snow). The data cover the past 2,000 years without gaps, and are the result of a compilation of measurements analysed by dozens of laboratories around the world, including CSIRO, the Bureau of Meteorology’s Cape Grim Station, NOAA, AGAGE and the Scripps Institution of Oceanography, among others. Read More here
Category Archives: Impacts Observed & Projected
29 May 2017, Independent, Great Barrier Reef can no longer be saved, Australian experts concede. The Great Barrier Reef – a canary in the coal mine for global warming – can no longer be saved in its present form partly because of the “extraordinary rapidity” of climate change, experts have conceded. Instead, action should be taken to maintain the World Heritage Site‘s ‘ecological function’ as its ecological health declines, they reportedly recommended. Like coral across the world, the reef has been severely damaged by the warming of the oceans with up to 95 per cent of areas surveyed in 2016 found to have been bleached. Bleaching is not always fatal but a study last year found the “largest die-off of corals ever recorded” with about 67 per cent of shallow water coral found dead in a survey of a 700km stretch. Now experts on a committee set up by the Australian government to improve the health of the reef have revealed that they believe the lesser target of maintaining its “ecological function” is more realistic. In a recent communique, the expert panel said they were “united in their concern about the seriousness of the impacts facing the Reef and concluded that coral bleaching since early 2016 has changed the Reef fundamentally”. “There is great concern about the future of the Reef, and the communities and businesses that depend on it, but hope still remains for maintaining ecological function over the coming decades,” it said. “Members agreed that, in our lifetime and on our watch, substantial areas of the Great Barrier Reef and the surrounding ecosystems are experiencing major long-term damage which may be irreversible unless action is taken now. Read More here
27 May 2017, Climate News Network, Climate change is turning Antarctic green.Plant life is flourishing on the Antarctic Peninsula, indicating a dramatic increase in the rate of warming due to climate change. Antarctica is getting greener. British biologists have documented a four-fold or even five-fold increase in plant growth on the Antarctic Peninsula. They identify the sudden burgeoning of green things as an indicator that the continent is responding to climate change. In fact, only a tiny fraction of the south polar land mass is home to any plant life, but the first explorers observed mosses growing on the 600km of the peninsula.Antarctic climate In a climate in which temperatures rarely go much higher than freezing, mosses grow slowly – and hardly ever decompose. So any mossy bank becomes a reliable record of shifts in climate dating back thousands of years. Researchers from the University of Exeter in the UK, and colleagues from the University of Cambridge and the British Antarctic Survey, report in Current Biology that they tested five ice cores from three sites and found major biological changes had occurred over the past 50 years right across the Antarctic Peninsula. “Temperature increases over roughly the past half-century on the Antarctic Peninsula have had a dramatic effect on moss banks growing in the region” The Arctic has entered a phase of dramatic warming: researchers have documented the advance of green growth across the tundra and even the advance of exotic infections in the animal population. Warming in the southern continent has been much more sluggish, but, even in the frozen interior, melting has been observed. And where there is sunlight and liquid water and bare rock, there are the conditions for green growth. Read More here
23 May 2017, The Conversation, Australian farmers are adapting to climate change. 2016-17 has been a great year for Australian farmers, with record production, exports and profits. These records have been driven largely by good weather, in particular a wet winter in 2016, which led to exceptional yields for major crops. Unfortunately, these good conditions go very much against the long-term trend. Recent CSIRO modelling suggests that changes in climate have reduced potential Australian wheat yields by around 27% since 1990. While rising temperatures have caused global wheat yields to drop by around 5.5% between 1980 and 2008, the effects in Australia have been larger, as a result of major changes in rain patterns. Declines in winter rainfall in southern Australia have particularly hit major broadacre crops (like wheat, barley and canola) in the key southeastern and southwestern cropping zones. There is strong evidence that these changes are at least partly due to climate change. Climate change is affecting farm productivity A recent study by the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) confirms that changes in climate have had a negative effect on the productivity of cropping farms, particularly in southwestern Australia and southeastern Australia. In general, the drier inland parts of the cropping zone have been more heavily affected, partly because these areas are more sensitive to rainfall decline. Smaller effects have occurred in the wetter zones closer to the coast. Here less rain can have little effect on – and can even improve – crop productivity. Farmers are reacting However, it’s not all bad news. The study finds that Australian farmers are making great strides in adapting to climate change. Much has been written about the fact that farm productivity in Australia has essentially flatlined since the 1990s, after several decades of consistent growth. The ABARES research suggests that changes in climate go some way towards explaining this slowdown. After controlling for climate, there has been relatively strong productivity growth on cropping farms over the past decade. However, while farms have been improving, these gains have been offset by deteriorating conditions. The net result has been stagnant productivity. Read More here