14 March 2016, The Conversation, Tipping point: how we predict when Antarctica’s melting ice sheets will flood the seas. Antarctica is already feeling the heat of climate change, with rapid melting and retreat of glaciers over recent decades. Ice mass loss from Antarctica and Greenland contributes about 20% to the current rate of global sea level rise. This ice loss is projected to increase over the coming century. A recent article on The Conversation raised the concept of “climate tipping points”: thresholds in the climate system that, once breached, lead to substantial and irreversible change. Such a climate tipping point may occur as a result of the increasingly rapid decline of the Antarctic ice sheets, leading to a rapid rise in sea levels. But what is this threshold? And when will we reach it? What does the tipping point look like? The Antarctic ice sheet is a large mass of ice, up to 4 km thick in some places, and is grounded on bedrock. Ice generally flows from the interior of the continent towards the margins, speeding up as it goes. Where the ice sheet meets the ocean, large sections of connected ice – ice shelves – begin to float. These eventually melt from the base or calve off as icebergs. The whole sheet is replenished by accumulating snowfall. Floating ice shelves act like a cork in a wine bottle, slowing down the ice sheet as it flows towards the oceans. If ice shelves are removed from the system, the ice sheet will rapidly accelerate towards the ocean, bringing about further ice mass loss. A tipping point occurs if too much of the ice shelf is lost. In some glaciers, this may spark irreversible retreat. Read More here
Category Archives: The Science
11 March 2016, Science Daily, Science can now link climate change with some extreme weather events. Extreme weather events like floods, heat waves and droughts can devastate communities and populations worldwide. Recent scientific advances have enabled researchers to confidently say that the increased intensity and frequency of some, but not all, of these extreme weather events is influenced by human-induced climate change, according to an international National Academies of Science, Engineering, and Medicine report released March 11. “In the past, many scientists have been cautious of attributing specific extreme weather events to climate change. People frequently ask questions such as, ‘Did climate change cause Hurricane Sandy?’ Science can’t answer that because there are so many relevant factors for hurricanes. What this report is saying is that we can attribute an increased magnitude or frequency of some extreme weather events to climate change,” said David Titley, professor of practice in Penn State’s Department of Meteorology and founding director of Penn State’s Center for Solutions to Weather and Climate Risk, who chaired the committee that wrote the report. The committee found that scientists can now confidently attribute some heat waves and cold events, and to a lesser degree droughts and extreme rainfall, to human-caused climate change. Even a decade ago, many scientists argued that research could not confidently tie any specific weather events to climate change, which the committee reports today is no longer true today. Read More here
10 March 2016, The Guardian, Dangerous global warming will happen sooner than thought – study. Australian researchers say a global tracker monitoring energy use per person points to 2C warming by 2030. The world is on track to reach dangerous levels of global warming much sooner than expected, according to new Australian research that highlights the alarming implications of rising energy demand. University of Queensland and Griffith University researchers have developed a “global energy tracker” which predicts average world temperatures could climb 1.5C above pre-industrial levels by 2020. That forecast, based on new modelling using long-term average projections on economic growth, population growth and energy use per person, points to a 2C rise by 2030. The UN conference on climate change in Paris last year agreed to a 1.5C rise as the preferred limit to protect vulnerable island states, and a 2C rise as the absolute limit. The new modelling is the brainchild of Ben Hankamer from UQ’s institute for molecular bioscience and Liam Wagner from Griffith University’s department of accounting, finance and economics, whose work was published in the journal Plos One on Thursday. It is the first model to include energy use per person – which has more than doubled since 1950 – alongside economic and population growth as a way of predicting carbon emissions and corresponding temperature increases. The researchers said the earlier than expected advance of global warming revealed by their modelling added a new found urgency to the switch from fossil fuels to renewables. Read More here
10 March 2016, Washington Post: Atmospheric carbon dioxide concentrations have spiked more in the period from February 2015 to February 2016 than in any other comparable period dating back to 1959, according to a scientist with the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory. The change in average concentrations from February of last year to February of this year was 3.76 parts per million at the storied Mauna Loa Observatory in Hawaii, leaving the concentration at 404.02 parts per million for February, based on preliminary data. Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network, confirmed that the increase, reported previously by New Scientist, represented a record year-over-year growth for Mauna Loa. He also said that in addition to the stark rise in carbon dioxide levels over the past year, researchers have now observed four straight years of increases of more than 2 parts per million in the atmosphere. “We’ve never seen that,” Tans said. “That’s unprecedented.” Read More here