Populations covered by governments that have declared a climate emergency now exceed 25 million citizens in four English-speaking countries, with over 12 million of these living in the United Kingdom.
Climate Emergency 1st Feb 2019 read more »
The global weather is about to get worse. The melting polar ice sheets will mean rainfall and windstorms could become more violent, and hot spells and ice storms could become more extreme. This is because the ice sheets of Greenland and Antarctica are melting, to affect what were once stable ocean currents and airflow patterns around the globe. Planetary surface temperatures could rise by 3°C or even 4°C by the end of the century. Global sea levels will rise in ways that would “enhance global temperature variability”, but this might not be as high as earlier studies have predicted. That is because the ice cliffs of Antarctica might not be so much at risk of disastrous collapse that would set the glaciers accelerating to the sea. The latest revision of evidence from the melting ice sheets in two hemispheres – and there is plenty of evidence that melting is happening at ever greater rates – is based on two studies of what could happen to the world’s greatest reservoirs of frozen freshwater if nations pursue current policies, fossil fuel combustion continues to increase, and global average temperatures creep up to unprecedented levels.
Climate News Network 15th February 2019 read more »
Prof Jonathan Bamber is a professor of glaciology at the University of Bristol and the current president of the European Geosciences Union (EGU). The ice sheets are the slowest-responding components of the climate system. They are, if you like, the supertankers of the climate system. Once you send them in a certain direction, they’re going to carry on in that direction for centuries – because their response time to external forces is relatively long. They respond more slowly than the oceans, the atmosphere and everything else. There are parts around the periphery of the ice sheets where they can respond quite quickly, but the whole system – the whole of the Antarctic ice sheet is a whole continent, one and a half times larger than Australia – that responds slowly. One of the challenges for us is that our observational record of what has happened to the ice sheets is rather short. We can look at paleo-climate data, so we can try and infer what the ice sheets did in the past based on paleo proxies for sea level rise over the last 100,000 years or something like that – but that’s a very imprecise measure. It’s an indirect measure of how the ice sheets are responding to external forcing and climate change. So, our satellite record – a high-precision, high-accuracy satellite record – is only about 30 years long. That’s not really sufficient to tell us how they might respond on a centennial timescale or something like that. The other problem is that there are highly non-linear responses of ice sheets to external forcing. We might just nudge them a little bit – and we might see quite a large response over decades to centuries. Identifying those transitions in state from one state to another is quite difficult in climate modelling, in general, when you have what’s called “hysteresis” in the system. That’s one of the reasons.
Carbon Brief 14th Feb 2019 read more »