3 August 2015, Potsdam Institute, CO2 removal cannot save the oceans – if we pursue business as usual. Greenhouse-gas emissions from human activities do not only cause rapid warming of the seas, but also ocean acidification at an unprecedented rate. Artificial carbon dioxide removal (CDR) from the atmosphere has been proposed to reduce both risks to marine life. A new study based on computer calculations now shows that this strategy would not work if applied too late. CDR cannot compensate for soaring business-as-usual emissions throughout the century and beyond, even if the atmospheric carbon dioxide (CO2) concentration would be restored to pre-industrial levels at some point in the future. This is due to the tremendous inertia of the ocean system. Thus, CDR cannot substitute timely emissions reductions, yet may play a role as a supporting actor in the climate drama. Ocean acidification affects the shells of plankton like Pteropods. “Geoengineering measures are currently being debated as a kind of last resort to avoid dangerous climate change – either in the case that policymakers find no agreement to cut CO2 emissions, or to delay the transformation of our energy systems,” says lead-author Sabine Mathesius from GEOMAR Helmholtz Centre for Ocean Research Kiel and the Potsdam Institute for Climate Impact Research (PIK). “However, looking at the oceans we see that this approach carries great risks.” In scenarios of timely emissions reductions, artificially removing CO2can complement efforts. “Yet in a business-as-usual scenario of unabated emissions, even if the CO2 in the atmosphere would later on be reduced to the preindustrial concentration, the acidity in the oceans could still be more than four times higher than the preindustrial level,” says Mathesius. “It would take many centuries to get back into balance with the atmosphere.” Read More here
Category Archives: Ecosystem Stress
3 August 2015, Science Daily, Glaciers melting faster than ever. The World Glacier Monitoring Service has compiled worldwide data on glacier changes for more than 120 years. Together with its National Correspondents in more than 30 countries, the international service just published a new comprehensive analysis of global glacier changes. In this study, observations of the first decade of the 21st century (2001-2010) were compared to all available earlier data from in-situ, air-borne, and satellite-borne observations as well as to reconstructions from pictorial and written sources. “The observed glaciers currently lose between half a metre and one metre of its ice thickness every year — this is two to three times more than the corresponding average of the 20th century,” explains Michael Zemp, Director of the World Glacier Monitoring Service and lead author of the study. “Exact measurements of this ice loss are reported from a few hundred glaciers only. However, these results are qualitatively confirmed from field and satellite-based observations for tens of thousands of glaciers around the world.” Global glacier decline According to the international author team, the current rate of glacier melt is without precedence at global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. In addition, the study shows that the long-term retreat of glacier tongues is a global phenomenon. Read More here
2 August 2015, Climate News Network, Global temperatures have risen by 1°C in the past 150 years, and one scientist says doubling that level could unleash catastrophic sea level rise this century. The world is now halfway towards the internationally-agreed safety limit of a maximum 2°C rise in global average temperatures, researchers say. That limit seeks to prevent the global warming caused by the burning of fossil fuels exceeding 2°C above the pre-industrial global temperature. The UN’s Paris climate summit later this year aims to ensure that it is not breached. It appears that the human race has taken roughly 250 years to stoke global warming by 1°C. On present trends, we look likely to add the next 1°C far more quickly – across much of the world, many climate scientists believe, by the middle of this century. The research is published in the journal New Scientist, which commissioned it. As so often with climate projections, it needs qualifying and teasing apart. Some scientists, for example, warn that there’s uncertainty about just what the pre-industrial global temperature was. The New Scientist research is careful to be specific: it says global surface temperature is now passing 1°C of warming “relative to the second half of the 19th century”. Farewell, hiatus. And one of the four main trackers of temperature thinks that milestone will be passed only if there is a strong El Niño, the cyclic Pacific weather phenomenon that periodically brings widespread chaos in its wake. However, the research looks likely finally to lay to rest the argument that global warming is slowing and stuttering to a virtual halt, the so-called hiatus theory. Kevin Trenberth, of the USNational Center for Atmospheric Research in Boulder, Colorado, told New Scientist: “There’s a good chance the hiatus is over.” Read More here
1 August 2015, Climate Network News, Wildfire threat spreads across warming world. As climate change warms the world vegetation dries, rainfall patterns waver and the threat of wildfire spreads. Wildfire – nature’s way of turning fallen vegetation into the next season’s nutrients – is a growing hazard. In the last 35 years, the wildfire season has grown longer by a fifth, and wildfire is now a threat to one fourth of all the plant-covered land on the planet. US researchers report in Nature Communications that since 1970 the number of days without rain has increased by well over one day every decade. William Jolly of the US Forest Service in Missoula, Montana and colleagues say they examined the fire season worldwide for the study period, taking into consideration all the factors that are used to calculate fire hazard: wind, humidity and temperature, as well as rainfall levels. They found that the combined changes in the surface weather have meant that the fire season has increased so far by 18.7%. Worldwide, wildfires sear, scorch or incinerate about 350 million hectares of ground cover every year. Changes in the rainfall patterns were a factor, with the number of rain-free days increasing by 1.31 days per decade. The season of smoke and cinders and smouldering stumps had been extended almost everywhere. Read More here