‘Tipping points’ could exacerbate climate crisis, scientists fear

‘Tipping points’ could exacerbate climate crisis, scientists fear

SOURCE: The Guardian DATE: October 9, 2018 SNIP: Key dangers largely left out of the IPCC special report on 1.5C of warming are raising alarm among some scientists who fear we may have underestimated the impacts of humans on the Earth’s climate. The IPCC report sets out the world’s current knowledge of the impacts of 1.5C of warming and clearly shows the dangers of breaching such a limit. However, many scientists are increasingly worried about factors about which we know much less. These “known unknowns” of climate change are tipping points, or feedback mechanisms within the climate system – thresholds that, if passed, could send the Earth into a spiral of runaway climate change. Durwood Zaelke, founder of the Institute for Governance and Sustainable Development, said: “The IPCC report fails to focus on the weakest link in the climate chain: the self-reinforcing feedbacks which, if allowed to continue, will accelerate warming and risk cascading climate tipping points and runaway warming.” He pointed to water vapour in the air, which traps heat in the atmosphere, as well as the loss of polar ice, the collapse of permafrost, and the migration of tropical clouds towards the poles. Further unknowns include the effects of climate change on carbon sinks, such as soils and forests: higher temperatures could dry out some soils, causing them to release stored carbon into the air. But increased rainfall – a symptom of climate change in some regions – could in other areas be making it harder for forest soils to trap greenhouse gases such as...
Domino-effect of climate events could move Earth into a ‘hothouse’ state

Domino-effect of climate events could move Earth into a ‘hothouse’ state

SOURCE: The Guardian DATE: August 7, 2018 SNIP: A domino-like cascade of melting ice, warming seas, shifting currents and dying forests could tilt the Earth into a “hothouse” state beyond which human efforts to reduce emissions will be increasingly futile, a group of leading climate scientists has warned. This grim prospect is sketched out in a journal paper that considers the combined consequences of 10 climate change processes, including the release of methane trapped in Siberian permafrost and the impact of melting ice in Greenland on the Antarctic. The authors of the essay, published in Proceedings of the National Academy of Sciences, stress their analysis is not conclusive, but warn the Paris commitment to keep warming at 2C above pre-industrial levels may not be enough to “park” the planet’s climate at a stable temperature. “I do hope we are wrong, but as scientists we have a responsibility to explore whether this is real,” said Johan Rockström, executive director of the Stockholm Resilience Centre. “We need to know now. It’s so urgent. This is one of the most existential questions in science.” Rockström and his co-authors are among the world’s leading authorities on positive feedback loops, by which warming temperatures release new sources of greenhouse gases or destroy the Earth’s ability to absorb carbon or reflect heat. Their new paper asks whether the planet’s temperature can stabilise at 2C or whether it will gravitate towards a more extreme state. The authors attempt to assess whether warming can be halted or whether it will tip towards a “hothouse” world that is 4C warmer than pre-industrial times and far less supportive of...
Barents Sea seems to have crossed a climate tipping point

Barents Sea seems to have crossed a climate tipping point

SOURCE: Ars Technica DATE: June 26, 2018 SNIP: Many of the threats we know are associated with climate change are slow moving. Gradually rising seas, a steady uptick in extreme weather events, and more all mean that change will come gradually to much of the globe. But we also recognize that there can be tipping points, where certain aspects of our climate system shift suddenly to new behaviors. The challenge with tipping points is that they’re often easiest to identify in retrospect. We have some indications that our climate has experienced them in the past, but reconstructing how quickly a system tipped over or the forces that drove the change can be difficult. Now, a team of Norwegian scientists is suggesting it has watched the climate reach a tipping point: the loss of Arctic sea ice has flipped the Barents Sea from acting as a buffer between the Atlantic and Arctic oceans to something closer to an arm of the Atlantic. The Norwegian work doesn’t rely on any new breakthrough in technology. Instead, it’s built on the longterm collection of data. The Barents Sea has been monitored for things like temperature, ice cover, and salinity, in some cases extending back over 50 years. This provides a good baseline to pick up longterm changes. And, in the case of the Barents Sea in particular, it’s meant we’ve happened to have been watching as a major change took place. [N]ot only have we discovered a climate tipping point, but we’ve spotted it after the system has probably already flipped into a new regime. It also provides some sense of what to...
Mathematical Formula Predicts Global Mass Extinction Event in 2100

Mathematical Formula Predicts Global Mass Extinction Event in 2100

SOURCE: Motherboard DATE: September 20, 2017 SNIP: A new paper in Science Advances finds that a mass extinction period mirroring ones from our planet’s ancient past could be triggered when humanity adds a certain amount of carbon to the oceans, which are home to the majority of all plants and animals on our planet. The paper pegs that amount at 310 gigatons. According to lead author Daniel Rothman of MIT, based on projections from the Intergovernmental Panel on Climate Change, we’re on course to hit that number by 2100. After that, we enter “unknown territory.” Passing over this carbon threshold moves us “to the other side of the stability boundary,” Rothman [Daniel Rothman of MIT] told me. It’s not that on Jan. 2, 2100, all species on our planet begin to apocalyptically die off. “The next day, everybody wakes up and goes to work as normal,” he said. It might take 10,000 years for a true disaster to play out. We’re rapidly moving towards a tipping point echoed in Earth’s ancient past. If we continue at this pace, we’ll reach it within our lifetimes, with implications that aren’t yet...