1. From The brutal logic of climate change
By David Roberts on Dec 6,
2011https://grist.org/climate-change/2011-12-05-the-brutal-logic-of-climate-change/ Kevin Anderson, former Director, U.K. Tyndall Energy Program.
“...a 4 degrees C future is incompatible with an organized global community,
is likely to be beyond ‘adaptation’,
is devastating to the majority of ecosystems,
and has a high probability of not being stable.”**************************
2. From: Turn Down the Heat - Why a 4°C Warmer World Must be Avoided, A Report for the World Bank by the Potsdam Institute for Climate Impact Research and Climate Analytics.
2012http://documents.worldbank.org/curated/en/865571468149107611/pdf/NonAsciiFileName0.pdf"
The 4°C scenarios are devastating: the inundation of coastal cities; increasing risks for food production potentially leading to higher malnutrition rates; many dry regions becoming dryer, wet regions wetter; unprecedented heat waves in many regions, especially in the tropics; substantially exacerbated water scarcity in many regions; increased frequency of high-intensity tropical cyclones; and irreversible loss of biodiversity, including coral reef systems.
And most importantly, a 4°C world is so different from the current one that it comes with high uncertainty and new risks that threaten our ability to anticipate and plan for future adaptation needs."
"It would be so dramatically different from today’s world that it is hard to describe accurately; much relies on complex projections and interpretations."
"We are well aware of the uncertainty that surrounds these scenarios and we know that different scholars and studies sometimes disagree on the degree of risk."
"Finding ways to avoid that scenario is vital for the health and welfare of communities around the world. While every region of the world will be affected, the poor and most vulnerable would be hit hardest.
A 4°C world can, and must, be avoided."
"Warming would not stop there. Because of the slow response of the climate system, the greenhouse gas emissions and concentrations that would lead to warming of 4°C by 2100 would actually commit the world to much higher warming, exceeding 6°C or more, in the long term, ..."
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3. From Climate tipping points — too risky to bet against
Timothy M. Lenton, Johan Rockström, Owen Gaffney, Stefan Rahmstorf, Katherine Richardson,
Will Steffen & Hans Joachim Schellnhuber, Nature. 27 November
2019https://www.nature.com/articles/d41586-019-03595-0"We argue that cascading effects might be common. Research last year analysed 30 types of regime shift spanning physical climate and ecological systems, from collapse of the West Antarctic ice sheet to a switch from rainforest to savanna. This indicated that exceeding tipping points in one system can increase the risk of crossing them in others. Such links were found for 45% of possible interactions.
In our view, examples are starting to be observed. For example, Arctic sea-ice loss is amplifying regional warming, and Arctic warming and Greenland melting are driving an influx of fresh water into the North Atlantic. This could have contributed to a 15% slowdown since the mid-twentieth century of the Atlantic Meridional Overturning Circulation (AMOC), a key part of global heat and salt transport by the ocean. Rapid melting of the Greenland ice sheet and further slowdown of the AMOC could destabilize the West African monsoon, triggering drought in Africa’s Sahel region. A slowdown in the AMOC could also dry the Amazon, disrupt the East Asian monsoon and cause heat to build up in the Southern Ocean, which could accelerate Antarctic ice loss."
"...the Earth system has been unstable across multiple timescales before, under relatively weak forcing caused by changes in Earth’s orbit.
Now we are strongly forcing the system, with atmospheric CO2 concentration and global temperature increasing at rates that are an order of magnitude higher than those during the most recent deglaciation."
Atmospheric CO2
"... is rapidly heading towards levels last seen some 50 million years ago — in the Eocene — when temperatures were up to 14 °C higher than they were in pre-industrial times.""
If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization. No amount of economic cost–benefit analysis is going to help us. We need to change our approach to the climate problem.
Act now
In our view, the evidence from tipping points alone suggests that we are in a state of planetary emergency: both the risk and urgency of the situation are acute "