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This is not remotely what the climate science literature says.
Misinformation like that article is becoming extreme and prevalent enough that there's a rapidly growing need for earth scientists to fact-check climate doomism. As if we didn't have enough to do already.
THREAD https://twitter.com/ClimateBen/status/1260699935302987777
Misinformation like that article is becoming extreme and prevalent enough that there's a rapidly growing need for earth scientists to fact-check climate doomism. As if we didn't have enough to do already.
THREAD https://twitter.com/ClimateBen/status/1260699935302987777
Often, a key giveaway that a claim about climate tipping points is unreliable is when a commentator assigns an EXACT temperature or CO2 threshold to a large-scale tipping point, or claims that it will be triggered within a very narrow range of future dates.
Frequently, the truth is scientists are still grappling with unknowns and cannot assign a threshold/timeline w such certainty or anything close to it. This is true for many earth systems: permafrost, forests, or ocean bio, and so it gets compounded for global climate as a whole.
We actually do not know *exactly* how much the planet warms for a given CO2 forcing - the “climate sensitivity” of the earth system. Similarly, we are still grappling with large ranges of uncertainty about climate feedbacks related to the carbon cycle. https://www.carbonbrief.org/analysis-how-carbon-cycle-feedbacks-could-make-global-warming-worse
For other systems often classified as tipping points, such as boreal forests or northern permafrost, scientists are actually fairly confident that there ISN’T a biome-wide tipping point for whole ecosystems - they're more like big systems with lots of local tipping points.
Landscapes have varied topography, hydrology, vegetation that make localities have different sensitivities to climate. I used the analogy of popcorn cooked over a low flame in this thread here: https://twitter.com/wang_seaver/status/1258521332884500480?s=20
Now, for some earth systems we actually do have high confidence about precise thresholds. For example, we are very certain that the Arctic Ocean will transition towards summers that are virtually free of sea ice for global mean warming above 2C: https://link.springer.com/article/10.1007/s40641-018-0113-2
Similarly, oceanographers and coral biologists are extremely confident that the overwhelming majority of coral reef habitat will be severely degraded at global mean warming of 2C. https://www.nature.com/articles/nclimate1674
But as an oceanographer who specialized in studying the marine carbon cycle, I found the linked op-ed in my OP to be of such poor quality in terms of scientific accuracy as to make my eyes bleed.
The claims about the ocean carbon cycle are particularly inaccurate.
The claims about the ocean carbon cycle are particularly inaccurate.
The idea that the sign of the ocean carbon sink will reverse and that the ocean will begin net release of CO2 - and imminently, to boot - goes wildly against all understanding of ocean chemistry, physics, and paleoclimate.
The overwhelming scientific understanding is that the ocean will continue to absorb CO2, but that climate change may affect the strength of that carbon sink.
See this review for more info: https://www.earth-syst-dynam.net/6/327/2015/
See this review for more info: https://www.earth-syst-dynam.net/6/327/2015/
No oceanographer thinks the net sign of the ocean carbon sink is likely to change due to global warming. In fact, we know on geological timescales, it will be ocean uptake of carbon and chemical reactions with sediments that will eventually bring atmospheric CO2 lvls back down.
Perhaps the Bangkok Post contributor was simply referring to the hypothesis that seafloor frozen methane could release large quantities of carbon in response to warming?
Recent research has found the risk to be much lower than we thought a decade ago.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GB005011 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016RG000534
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GB005011 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016RG000534
Overall, runaway climate change would require that tipping points and carbon cycle feedbacks would cumulatively produce enough greenhouse gases or additional warming to warm the planet by a couple degrees irregardless of actions to curb future human emissions.
This appears highly unlikely in the near future (several decades) based on current knowledge - even fairly aggressive estimates for carbon release from the Amazon or from permafrost in a warmer world over this century, for example, are small relative to human emissions.
Tipping points or carbon cycle feedbacks independently producing a couple degrees of additional warming only becomes more of a possibility over longer timescales (beyond a century from now) under extreme emissions scenarios (we burn a huge fraction of world's known coal).
The bottom line is we don’t really know whether “runaway climate change” is possible, but we are fairly sure that it requires a lot of worst-case assumptions in order to come about, and while it hasn’t been ruled out it also hasn’t been satisfactorily explored yet alone proven.
That doesn’t change the fact those uncertainties are worrisome, and that we DO know enough about climate science to realize that we have an infinite amount of reasons to prioritize ambitious climate action even based on what we CAN confidently predict.
But at any rate, it is irresponsible for climate folks to take absolute worst-case outcomes that are still seen as highly subject to uncertainties by scientists and represent them as if they are both certain and likely.
Worst-case climate outcomes must be communicated as such. Scientific uncertainties must be acknowledged. https://twitter.com/wang_seaver/status/1252280700880908288?s=20
Doing this in no way diminishes the urgency or importance of actions to reduce global emissions.
To be absolutely clear, while there are things we don’t know, we do know more than enough to make an overwhelming case for action.
To be absolutely clear, while there are things we don’t know, we do know more than enough to make an overwhelming case for action.
It is an important responsibility of journalists and climate communicators to report climate science as accurately as they can. We scientists do our best, but we’re busy people. Help us by taking your time, reading the scientific literature, emailing experts to double-check.
Quality climate communication takes LOTS of time. Complete accuracy is the only acceptable standard to hold oneself to - that’s the bar scientists are held up to, after all.
We all agree climate is important, so let’s strive together to do the issue justice.
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We all agree climate is important, so let’s strive together to do the issue justice.
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