30 June 2016, NASA. Why a half-degree temperature rise is a big deal. The Paris Agreement, which delegates from 196 countries hammered out in December 2015, calls for holding the ongoing rise in global average temperature to “well below 2 °C above pre-industrial levels,” while “pursuing efforts to limit the temperature increase to 1.5 °C.” How much difference could that half-degree of wiggle room (or 0.9 degree on the Fahrenheit scale) possibly make in the real world? Quite a bit, it appears. The European Geosciences Union published a study in April 2016 that examined the impact of a 1.5 degree Celsius vs. a 2.0 C temperature increase by the end of the century, given what we know so far about how climate works. It found that the jump from 1.5 to 2 degrees—a third more of an increase—raises the impact by about that same fraction, very roughly, on most of the phenomena the study covered. Heat waves would last around a third longer, rain storms would be about a third more intense, the increase in sea level would be approximately that much higher and the percentage of tropical coral reefs at risk of severe degradation would be roughly that much greater. But in some cases, that extra increase in temperature makes things much more dire. At 1.5 C, the study found that tropical coral reefs stand a chance of adapting and reversing a portion of their die-off in the last half of the century. But at 2 C, the chance of recovery vanishes. Tropical corals are virtually wiped out by the year 2100. Read More here
Tag Archives: Agriculture
18 May 2016, The Conversation, Are toxic algal blooms the new normal for Australia’s major rivers? For much of this year, up to 1,700 kilometres of the Murray River has been hit by a serious outbreak of potentially toxic blue-green algae, which has flourished in the hotter-than-average conditions. After three months, the river is now recovering with the arrival of wet weather. But we are unlikely to have seen the last of these poisonous microbes. Large blue-green algal blooms are a relatively new phenomenon in inland waterways. In 1991 an algal bloom affected more than 1,000 km of the Darling River, the first time such an event had been reported in an Australian river, and one of the few times internationally. It was an environmental disaster, killing livestock and striking a telling blow against Australia’s reputation as a clean, green farming nation. The response was decisive: a state of emergency was declared, and the bloom ultimately gave rise to significant investment by state and federal governments into freshwater research, particularly in the Murray-Darling Basin. Why no emergency now? Fast forward two and a half decades to the latest bloom afflicting the Murray River, one of Australia’s most socially, economically and culturally significant waterways. The past decade has seen four similar blooms on the Murray River: in 2007, 2009, 2010 and now. Yes, they have garnered press attention, but there has not been the same call to arms that we saw when the Darling River was struck in 1991. It is almost as if such significant environmental events are now simply seen as the new normal. Why the apparent complacency? The 2007, 2009 and 2010 algal blooms on the Murray River all happened during the Millennium Drought, and hence were probably ascribed to an aberration in the weather. In reality, the situation may have more to do with how we manage water in Australia – particularly during periods of scarcity, such as the one we may well be entering now. Read More here
4 April 2016, Science Daily, Water cycle instability is here to stay posing major political and economic risks. Adaptation to new risks: A vital necessity for development policies. The current instability and unpredictability of the world water cycle is here to stay, making society’s adaptation to new risks a vital necessity when formulating development policies, a UN water expert warns. Robert Sandford, the EPCOR Chair for Water and Climate Security at the United Nations University’s Canadian-based Institute for Water, Environment and Health (UNU-INWEH), says long-term water cycle stability “won’t return in the lifetime of anyone alive today.” “What we haven’t understood until now is the extent to which the fundamental stability of our political structures and global economy are predicated on relative stability and predictability of the water cycle — that is, how much water becomes available in what part of the year. As a result of these new water-climate patterns, political stability and the stability of economies in most regions of the world are now at risk.” Ontario Lieutenant-Governor Elizabeth Dowdeswell, a former Executive Director of the UN Environment Programme, and UN Under Secretary-General David Malone, Rector of UN University, are among several expert speakers joining Sandford in Ottawa Tuesday April 5 at UNU-INWEH’s day-long 20th anniversary public seminar, “Water: The Nexus of Sustainable Development and Climate Change.” The seminar will focus on national policy changes needed worldwide to achieve global water security — a pre-requisite for reaching the new global Sustainable Development Goals, or SDGs, agreed upon by world leaders in September 2015. Read More here
28 March 2016, Climate News Network, Plants’ heat response means fiercer heatwaves. Asia faces more extreme heat by mid-century as some plant species react unexpectedly to rising average temperatures, new research shows. Tomorrow’s heat waves could be even hotter than climate scientists have so far predicted. Maximum temperatures across the Asian continent from Europe to China could be 3°C to 5°C higher than previous estimates – because the forests and grasslands will respond in a different way. Australian scientists report in the journal Scientific Reports that they looked at the forecasts made by the Intergovernmental Panel on Climate Change under the notorious “business-as-usual” scenario, in which the world’s nations go on burning ever more fossil fuels, to release ever more greenhouse gases. The average global temperatures will rise steadily – but this rise will be accompanied by ever greater and more frequent extremes of heat. But then Jatin Kala of Murdoch University in Perth, Western Australia, and colleagues factored in the responses of the plants to rising temperatures.They looked at data from 314 species of plant from 54 research field sites. In particular, they investigated stomatas, tiny pores on the leaves through which plants absorb carbon dioxide and shed water to the atmosphere. Response crucial What matters is how vegetation responds to extremes of heat. Researchers have already established that plants respond, not always helpfully: extremes can alter the atmospheric chemistry unfavourably for plants, and certainly reduce crop yields. But other scientists have confirmed the so-called carbon dioxide fertilisation effect: as more carbon becomes available, plants use water more economically and so even though drylands may get drier the landscape can also get greener, and growth tends to begin ever earlier as winters get warmer, and spring arrives earlier. Read more here