10 November 2015, The Conversation, Ocean acidification: the forgotten piece of the carbon puzzle. Ocean acidification – the rise in ocean acidity due to the increased absorption of carbon dioxide (CO₂) – is often thought of as consequence of climate change. However, it is actually a separate, albeit very closely-related problem. Ocean acidification is often referred to as “the other CO₂ problem” because, like climate change, it is primarily a result of the increased emissions of this gas. Despite their common driver, though, the processes and impacts of ocean acidification and climate change are distinct. It should not be assumed that policies intended to deal with the climate will simultaneously benefit the oceans. The current emphasis of global climate policies on a warming target is a case in point. A narrow focus on temperature stabilisation, for example, opens the door for policy interventions that prioritise the reduction of greenhouse gases other than carbon dioxide. This is because non-CO₂ greenhouse gases — like methane and nitrous oxide, which can arise from agricultural and industrial processes — typically have a higher global warming potential and might even be less costly than CO₂ to reduce. In addition, several geoengineering schemes have been proposed to reduce the impacts of a warming climate. Yet such schemes often do nothing to address emissions, and may even exacerbate carbon absorption in the oceans. Read More here
Category Archives: Impacts Observed & Projected
9 November 2015, Science News, The past shows how abrupt climate shifts affect Earth. New research shows how past abrupt climatic changes in the North Atlantic propagated globally. The study, led by researchers from Centre for Ice and Climate at the University of Copenhagen’s Niels Bohr Institute, shows how interaction between heat transport in the ocean and the atmosphere caused the climatic changes to be expressed in different ways across the Southern Hemisphere. The results shows how forcing the climate system into a different state can trigger climate variations that spread globally and have very different impacts in different regions of Earth. This is important now, where rising atmospheric CO2 levels lead to global warming and may trigger abrupt climatic changes. The results have been published in the scientific journal Nature Geoscience. The history of climate on Earth is stored in tiny variations in kilometer-thick ice cores, sediments from lakes and oceans, and other natural archives that are layered down over thousands of years and works as archives of past temperatures. By recovering and deciphering these archives, researchers can reveal how and why the climate changed in the past, and in this way learn how the climate system may react in the future as the planet warms and the ice sheets melt. Read more here
9 November 2015, Carbon Brief, Global temperature rise set to hit 1C of warming this year, Met Office says. Scientists expect 2015 to be the first year where global annual average temperature passes 1C above pre-industrial levels. As of the end of September, global temperature is sitting at 1.02C above the 1850-1900 average, and is “expected to hold” for the rest of the year, a short Met Office report says. This is another piece of evidence of “systematic warming” of the Earth’s climate, saysDr Peter Stott, head of the climate monitoring and attribution at the Met Office Hadley Centre. The news generated some media interest, including headlines in the BBC and Guardian. It comes on the same day as the World Meteorological Organisation announced that the global average concentration of carbon dioxide surpassed 400 parts per million in spring 2015, notes the Independent. ‘Important marker’ Each year, major meteorological organisations around the world calculate the global average surface temperature. It’s just one measure of how the world is changing in response to human-caused greenhouse gas emissions. These provisional figures for 2015 come from HadCRUT4, a dataset of observed global temperatures jointly put together by the UK Met Office and the Climatic Research Unit (CRU) at the University of East Anglia. The data suggests that 2015 will reach, and surpass, 1C above pre-industrial temperatures for the first time in human history. The cross in the top right-hand corner of the chart below shows where the 2015 temperature currently sits compared to the last 150 years. Read more here
9 November 2015, Renew Economy, Graph of the Day: Cities under water at 2°C and 4°C. Around half a billion people are at risk from sea level rise if the world continues on a business-as-usual path for carbon emissions, a new report has found – while limiting warming to the recommended 2°C would cut this risk by more than half. The US report by Climate Central, accompanied by an online interactive mapping system, shows that carbon emissions causing 4°C of warming – what business-as-usual points toward today – could lock in enough sea level rise to submerge land currently home to 470 to 760 million people as the “unstoppable rise” unfolds over centuries. The research also reveals, however, that aggressive carbon cuts limiting warming to 2°C could bring the number as low as 130 million people. The report – authored by Climate Central scientists Benjamin Strauss and Scott Kulp, and Anders Levermann of the Potsdam Institute for Climate Impact Research – assesses implications for all coastal nations and cities – post-2100 – using relationships between warming caused by carbon emissions, the long-term global sea level rise it locks in, and global elevation and population data. The news is worst for China, which is found to be most at risk with 145 million people living on land ultimately threatened by rising seas if emission levels are not reduced. Below are the mapped projections for Shanghai, at 4°C on the left, and 2°C on the right. Read More here