The rising seas’ cost may be US$27tn a year for the world by 2100 if it fails to meet the UN’s 2ºC global warming limit by then, with sea level rise of, at its worst, almost six feet (nearly two metres), new research says. A study led by the UK’s National Oceanography Centre (NOC) says the worldwide cost of flooding caused by rising sea levels, at their median level, could by 2100 be $14 trillion, if governments miss the United Nations target of keeping the rise in global temperatures, caused by unremitting fossil fuel use, to less than 2ºC above pre-industrial levels. But the extent and cost could be much higher. The target was agreed by 195 nations in Paris in 2015, with many politicians and most scientists urging them to treat 2ºC as a more modest and feasible limit while aiming if possible for 1.5°C. The cuts in greenhouse gas emissions already promised through the UN Framework Convention on Climate Change are not yet enough to achieve the 2ºC limit, let alone the more stringent figure, and much deeper cuts will be needed.
Climate News Network 4th July 2018 read more »
For biodiversity, the benefits of holding warming to 1.5C rather than 2C are clear. At 2C, for example, models project that 23% of the world’s plants could lose more than half of their range of suitable climate. This drops to 7-13% under 1.5C. But there is another side to how climate change could affect biodiversity – through the land management decisions we take as part of efforts to reduce greenhouse gas (GHG) levels in the atmosphere. Given that agriculture and forestry together are responsible for 24% (pdf) of global GHG emissions, we know that the land is going to be important for meeting either the 2C or 1.5C goals. Not least because, as we pursue efforts to reach a 1.5C limit, it becomes increasingly likely that we will need to ramp up how much CO2 the land surface absorbs from the atmosphere. This means applying “negative emissions” techniques that often need substantial land and water when deployed at scale.
Carbon Brief 4th July 2018 read more »