Newfie wrote:Musical chairs to the death!
dohboi wrote: 'we' do have some mechanism for 'coping,' however horribly flawed it may seem...Paris Accords. If they could have been strengthened and built on, and say a President Bernie Sanders and perhaps a few other somewhat enlightened world leaders had arisen and showed some true leadership, and pointed the way toward rapidly crashing carbon emissions while protecting many/most of the most vulnerable...
Newfie wrote: This doesn't extend to the death of humanity, in total or large parts there of, no matter if we act to reduce the carnage or not. That's new to us, individually.
In overshoot nature is merciful to the species by being merciless to the individuals
jedrider wrote:Nice article in NY Magazine. I think this is healthy to face reality and not live the lie.
I like that the article was mostly comprehensive that the threats are multiple and, for the most part, simultaneous.
The lukewarm optimism at the end is kind of a let down; reality cannot be taken in all at once.
...as volatility slowly starts to moderate.
Cid_Yama wrote:...as volatility slowly starts to moderate.
There is nothing whatsoever in the science to support this contention. Volatility will continue to increase well beyond the timeframe of conditions capable of supporting human life on this planet.
Ibon wrote:Cid_Yama wrote: Volatility will continue to increase well beyond the timeframe of conditions capable of supporting human life on this planet.
The upcoming volatility is a big unknown. At some point CO2 emissions will be radically reduced due to the corrections of human overshoot. At that point how many further generations will still be persevering through highly volatile climate conditions and how soon this will moderate?
100, 500, 1000, 10,000 years?
The answer to that is probably not in the fossil record.
Your suggestion that it will never moderate and that we will be extinct sounds less like science and more like a wrathful god condemning our species to burn with eternal fire for all our naughty behavior!
Plantagenet wrote:Ibon wrote:
This is a job for atmospheric chemistry!
Methane has very short life in the atmosphere. It is consumed by various chemical reactions and turns into other things, including CO2 in about 11 years. So any transient increases in atmospheric methane, whether caused by human fossil fuel use or by releases from warming permafrost, are completely consumed very quickly, allowing the atmosphere to fall back to a more moderate level of CH4 that is in balance with natural terrestrial methane production.
CO2, in contrast, survives for a longer time in the atmosphere, with estimates ranging from 700-1000 years. This means if human FF use were to stop and human CO2 emissions were to end in about a thousand years the atmosphere would drop back to some moderate level of CO2 concentration that would balance with natural terrestrial CO2 production.
Cheers!
At some point CO2 emissions will be radically reduced due to the corrections of human overshoot. ...and how soon this will moderate?
100, 500, 1000, 10,000 years?
Global warming is forever, some of the world's top climate scientists have concluded. Their research shows that carbon dioxide emitted from today's homes, cars and factories will continue to heat up the planet for hundreds of thousands of years.
It comes as a shock because most governments, and even many scientists, have assumed that carbon dioxide emissions would work their way out of the atmosphere in about a century, enabling it to clean itself fairly rapidly once the world switched to clean sources of energy.
But one of the main researchers – Professor David Archer of Chicago University – warns that "the climatic impacts of releasing fossil fuel carbon dioxide into the atmosphere will last longer than Stonehenge, longer than time capsules, far longer than the age of human civilisation so far. Ultimate recovery takes place on timescales of hundreds of thousands of years, a geologic longevity typically associated in public perceptions with nuclear waste."
Carbon dioxide mainly leaves the atmosphere by being soaked up by the oceans, but Professor Archer says that "the pervasive notion in the climate science community and in the public at large" that this happens relatively quickly is no longer valid. He and other leading scientists spell out why in a paper to be published in the journal Annual Reviews of Earth and Planetary Sciences.
"The ocean is getting fed up with absorbing our CO2," he says. The surface waters, about 100 metres deep, which used to sop up the gas quite fast, are now getting saturated with it – turning acid in the process – and so decreasing their uptake. They need to be replaced with fresh water from deep down, but this overturning circulation "takes centuries or a millennium". And global warming is expected to slow this down: the hotter the surface layer becomes, the longer the replenishment takes.
Indeed, the forthcoming paper will add, research shows that even this renewing process will not be enough to remove all the vast amounts of carbon dioxide that humanity is now adding to the atmosphere. Much of it will have to wait hundreds of thousands of years before being removed by another, infinitely slower, process: the natural weathering of rocks, which incorporates the gas into other substances. And the more pollution that is emitted now, the worse this will become.
The models presented here give a broadly coherent picture of the fate of fossil fuel CO2 released into the atmosphere. Equilibration with the ocean will absorb most of it on a timescale of 2 to 20 centuries. Even if this equilibration were allowed to run to completion, a substantial fraction of the CO2, 20–40%, would remain in the atmosphere awaiting slower chemical reactions with CaCO3 and igneous rocks. The remaining CO2 is abundant enough to continue to have a substantial impact on climate for thousands of years. The changes in climate amplify themselves somewhat by driving CO2 out of the warmer ocean. The CO2 invasion has acidified the ocean, the pH of which is largely restored by excess dissolution of CaCO3 from the sea floor and on land and, ultimately, by silicate weathering on land. The recovery of ocean pH restores the ocean’s buffer capacity to absorb CO2, tending to pull CO2 toward lower concentrations over the next 10,000 years. The land biosphere has its greatest impact within the first few centuries, which is when CO2 peaks. Nowhere in these model results or in the published literature is there any reason to conclude that the effects of CO2 release will be substantially confined to just a few centuries. In contrast, generally accepted modern understanding of the global carbon cycle indicates that climate effects of CO2 releases to the atmosphere will persist for tens, if not hundreds, of thousands of years into the future.
Cid_Yama wrote:Greenhouse gases will heat up planet 'forever'
– Professor David Archer of Chicago University – warns that "The ocean is getting fed up with absorbing our CO2,"
Cid_Yama wrote:Greenhouse gases will heat up planet 'forever'
Abstract
CO2 released from combustion of fossil fuels equilibrates among the various carbon reservoirs of the atmosphere, the ocean, and the terrestrial biosphere on timescales of a few centuries. However, a sizeable fraction of the CO2 remains in the atmosphere, awaiting a return to the solid earth by much slower weathering processes and deposition of CaCO3. Common measures of the atmospheric lifetime of CO2, including the e-folding time scale, disregard the long tail. Its neglect in the calculation of global warming potentials leads many to underestimate the longevity of anthropogenic global warming. Here, we review the past literature on the atmospheric lifetime of fossil fuel CO2 and its impact on climate, and we present initial results from a model intercomparison project on this topic. The models agree that 20–35% of the CO2 remains in the atmosphere after equilibration with the ocean (2–20 centuries). Neutralization by CaCO3 draws the airborne fraction down further on timescales of 3 to 7 kyr.
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