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