13 December 2015, Climate News Network, Cold water poured on warming pause. COP21: Scientists say pressure from climate sceptic voices may have led to credibility being given to the mistaken claim that there is evidence of a hiatus in global warming. The so-called, and much debated, hiatus in global warming may never have happened, according to new research The scientists say there is no substantive evidence for a recent flattening of the curve in the increase in global average temperatures: in other words, no pause, no slowdown in global warming. “We suggest,” they add, “that the use of those terms is therefore inaccurate.” But first, and briefly, the story so far. In the 1990s, planetary temperatures rose steadily, reaching a then all-time high in 1998. In the 21st century, temperatures on average continued to rise, but the rate of increase seemed to be lower. Even so, 13 of the 14 hottest years ever have happened this century, and 2014 was thehottest year ever. Denialists, sceptics and contrarians seized on the apparent slowdown and claimed that global warming had stopped. And teams of climate scientists were drawn, like moths to a flame, again and again to the question of whether there really was a slowdown − and, if so, why. Unexplained data They kept doing so because that is how science works: researchers worry away at unexplained data. They evaluate each other’s hypotheses, try to kick them to death, and then propose an alternative. So, in the course of the last three years, scientists have variously accepted that global warming was never going to proceed at a steady, inexorable rate, that some Atlantic Ocean cycle might be at play to damp atmospheric temperatures, or that the heat might have disappeared into the Pacific depths. They have also proposed that an increase in volcanic activity may have masked solar radiation, and that extremes of temperature were on the increase even if the average appeared not to be rising intemperately. Read More here
Monthly Archives: December 2015
13 December 2015, The Guardian, Malcolm Turnbull lifts Abbott ban on government finance for wind power. Malcolm Turnbull has lifted the ban imposed by Tony Abbott on wind investment by the Clean Energy Finance Corporation (CEFC) before it was officially enacted, even though it remains Coalition policy to abolish the green bank. A spokeswoman for the prime minister said the new CEFC investment mandate – issued by the environment minister, Greg Hunt, and the finance minister, Mathias Cormann – reflected “the Turnbull government’s strong support for renewables and innovation”. “The mandate puts the CEFC’s focus on new and emerging renewables technologies, rather than supporting well-established technologies that are financially viable without government support,” the spokeswoman said. In the wake of the new mandate and the Paris agreement, various stakeholders in the renewable sector were optimistic that the CEFC decision could reboot the government’s relationship with the clean energy industry. The new mandate says: “As part of its investment activities in clean energy technologies, the corporation must include a focus on supporting emerging and innovative renewable technologies and energy efficiency, such as large scale solar, storage associated with large and small scale solar, offshore wind technologies, and energy efficient technologies for cities and the built environment.” Read More here
11 December 2015, The Conversation, Climate and the rise and fall of civilizations: a lesson from the past. 2015 will likely be the hottest year on record, beating the previous record set only in 2014. It is also likely to be the first year the global average temperature reaches 1℃ above pre-industrial temperatures (measured from 1880-1899). Global warming is raising temperatures, and this year’s El Niño has pushed temperatures higher still. Although 2015 is unusually hot, 1℃ symbolically marks the halfway point to 2℃, widely considered to be the threshold of “dangerous” climate change. In fact an additional 0.5-1℃ is actually masked by sulphur aerosols which we have added to the atmosphere alongside greenhouse gases. A temperature level of 1℃ (above pre-industrial levels) is similar to or warmer than the peak temperatures of the early Holocene epoch approximately 8,000-7,200 years ago. Studies of the early Holocene provide clues to what was such a world like. The climate roller-coaster The last ice age (or Last Glacial Maximum) peaked around 26,000 years ago. The earth warmed over the coming millennia, driven by an increase in radiation from the sun due to changes in the earth’s orbit (the Milankovic cycles) amplified by CO₂ released from warming water, which further warmed the atmosphere. But even as the earth warmed it was interrupted by cooler periods known as “stadials”. These were caused by melt water from melting ice sheets which cool large regions of the ocean. Marked climate variability and extreme weather events during the early Holocene retarded development of sustainable agriculture. Sparse human settlements existed about 12,000 – 11,000 years ago. The flourishing of human civilisation from about 10,000 years ago, and in particular from 7,000 years ago, critically depended on stabilisation of climate conditions which allowed planting and harvesting of seed and growing of crops, facilitating growth of villages and towns and thereby of civilisation. Read More here
10 December 2015, Science Daily, Trees either hunker down or press on in a drying and warming western US climate. In the face of adverse conditions, people might feel tempted by two radically different options — hunker down and wait for conditions to improve, or press on and hope for the best. It would seem that trees employ similar options when the climate turns dry and hot. Two University of Washington researchers have uncovered details of the radically divergent strategies that two common tree species employ to cope with drought in southwestern Colorado. As they report in a new paper in the journal Global Change Biology, one tree species shuts down production and conserves water, while the other alters its physiology to continue growing and using water. As the entire western United States becomes warmer and drier through human-made climate change, these findings shed light on how woody plants may confront twin scourges of less water and hot weather. The authors, UW biology graduate student Leander Anderegg and biology professor Janneke Hille Ris Lambers, wanted to understand if different tree species employ similar coping strategies for drought, and how these strategies would affect their future ranges in a warmer and drier climate. They compared how two common tree species differ in terms of shape, growth rate and physiology across wet and dry portions of their native ranges. “We really wanted to identify the entire suite of strategies that a plant can use to grow in drier environments, as well as which of these strategies each tree would employ,” said Hille Ris Lambers. Read more here