See what Dec 2015 to Feb 2016 looked like, temperature-wise:
2016 started off way hotter than 2015. A sudden jump like this is called a step change. If you expect we'll now cool off to our previous decadal average, forget that. We've "leveled up".
The current warming surge amounts to what’s called a step change — a practically instantaneous shift in our planet’s climate.
This sudden shift in temperature has arrived because of a confluence of events: Long-term global warming, the multiyear effect of El Niño, and extreme weather — including persistent heat waves at the regional scale.
The major cause of February’s exceptional warmth is global warming,…
… El Niño can’t explain all or even most of the current warming spike — especially the warmth in the Arctic.
Based on the Met Office’s estimates and my calculations, 2016 will probably be around 1.1 to 1.5 degrees above the 1850-1900 average. An annual breach of 2 degrees could happen as soon as 2030, according to climate model simulations,…
According to a five-year prediction from the Met Office, global temperatures may fall slightly over the next year or two, as the El Niño wanes and temporarily cooler ocean temperatures associated with La Niña take hold. But global warming will make that respite brief: 2018, 2019 and 2020 will likely be warmer than 2015, and the warming trend is expected to continue long after that. Sixteen of the 18 years that followed the last big El Niño (1997-98) were warmer than 1997. [emphasis mine]
Step changes also happen in other climate issues, such as the rate of sea level rise. Sudden jumps in the rate of melt indicate a tipping point was passed, and new self-reinforcements have kicked in.
Doubling times in non linear events often don’t fit a pure exponential curve — instead tending to follow a series of spikes and recessions with major transitional events coming at the end of any ‘curve.’ [emphasis mine]
Our path ahead: major transitional events kicking us into new regimes of change we'll hate.
Processes of vegetation water-stress and soil moisture are not adequately modeled in current climate science. Julia Greene and Pierre Gentine's study found that the ability of land plants to absorb carbon has been halved already by swings in soil moisture from droughts and heat waves. Their model suggests that by mid-century land carbon absorption will drop enough to, by itself, cause a large increase in CO2.
"It is unclear ... whether the land can continue to uptake anthropogenic emissions at the current rates,"...
... Gentine and Green analyzed net biome productivity (NBP), … equal to the net ecosystem production minus the carbon lost from disturbance like a forest fire or a forest harvest.
They were able to isolate the effects of changes in long-term soil moisture trends (i.e. drying) as well as short-term variability (i.e., the effects of extreme events such as floods and droughts) on the ability of the land to uptake carbon.
"We saw that the value of NBP, in this instance a net gain of carbon on the land surface, would actually be almost twice as high if it weren't for these changes (variability and trend) in soil moisture," says Green ...
"This is a big deal! If soil moisture continues to reduce NBP at the current rate, and the rate of carbon uptake by the land starts to decrease by the middle of this century -- as we found in the models -- we could potentially see a large increase in the concentration of atmospheric CO2 and a corresponding rise in the effects of global warming and climate change." [emphasis mine]
Eight of the next-generation climate models being developed to produce the United Nation's 2021 Climate assessment are predicting significantly higher climate sensitivity than past models, around 5 degrees C for CO2 doubling.
Modelers are struggling to identify which of their refinements explain this heightened sensitivity...
But the trend “is definitely real. There’s no question,”says Reto Knutti, a climate scientist at ETH Zurich in Switzerland.
The new simulations are only now being discussed at meetings, and not all the numbers are in, so “it’s a bit too early to get wound up,” says John Fyfe, a climate scientist at the Canadian Centre for Climate Modelling and Analysis in Victoria, whose model is among those running much hotter than in the past. “But maybe we have to face a reality in the future that’s more pessimistic than it was in the past.”
The sixth CMIP is now at least a year late.
Attention East Coast people! A step change in your hurricane frequency is due in 2040.
A new paper ... finds that climate change could alter wind shear in a way that could deliver more powerful hurricanes to the East Coast. The study is authored by scientists from Columbia University's Lamont-Doherty Earth Observatory and the National Oceanic and Atmospheric Administration.
... as hurricanes move northwestward out of the tropical Atlantic, a strong vertical wind shear along the East Coast prevents the storm from gaining strength, thus providing a protective barrier to strong landfalling hurricanes. Lamont Research Professor Mingfang Ting had the idea to build upon Kossin's findings with the application of her own modeling to explore how a changing climate might affect this wind shear pattern.
... this study was the first to find that rising anthropogenic greenhouse gases in the atmosphere will weaken the vertical wind shear along the East Coast which will, in turn, enable further intensification of hurricanes that make landfall in this region.
"Once the natural protection is eroded by greenhouse gas warming, we may experience unprecedented hurricane intensification along the East Coast that can lead to stronger landfalling storms and higher storm surges in the future," Ting explains. "This is on top of the stronger tropical cyclone strength expected from the warmer sea surface temperature that we are already aware of."
One of the models with a larger number of simulations indicated that these effects could start to be seen around the year 2040. [emphasis mine]
You've seen projected hurricane paths veer northeast, avoiding landfall, year after year. That invisible wind shear barrier will go away. Boom!
And the tRump administration is conveniently eliminating federal agencies' predictions of the effects of climate change past 2040.
... parts of the federal government will no longer fulfill what scientists say is one of the most urgent jobs of climate science studies: reporting on the future effects of a rapidly warming planet and presenting a picture of what the earth could look like by the end of the century if the global economy continues to emit heat-trapping carbon dioxide pollution from burning fossil fuels.
The attack on science is underway throughout the government. In the most recent example, the White House-appointed director of the United States Geological Survey, James Reilly, a former astronaut and petroleum geologist, has ordered that scientific assessments produced by that office use only computer-generated climate models that project the impact of climate change through 2040, rather than through the end of the century, as had been done previously...
("Trump Administration Hardens its Attack on Climate Science", May 27, NYT; bolding added)
And we're seeing a bit of Godwin's Law too! The article also quotes a tRump appointee as saying "The demonization of carbon dioxide is just like the demonization of the poor Jews under Hitler"!
Sometimes passing a tipping point unleashes a cascade of feedbacks. Daniel Rothman found that four of five mass extinction events exhibited such an "excitation" (comparing the sudden change to a firing neuron), in which a particular rate of ocean acidification took over for 10,000 years.
MIT geophysics professor Daniel Rothman released new data on Monday showing that carbon levels today could be fast approaching a tipping point threshold that could trigger extreme ocean acidification similar to the kind that contributed to the Permian–Triassic mass extinction that occurred about 250 million years ago.
…the ocean model eventually reached a threshold which triggered what MIT called "a cascade of chemical feedbacks," or "excitation," causing extreme acidification and worsening the warming effects of the originally-added carbon.
Over the past 540 million years, these chemical feedbacks have occurred at various times, Rothman noted.
But the most significant occurances took place around the time of four out of the five mass extinction events—…
The planet may now be "at the precipice of excitation," Rothman told MIT News.
"We already know that our CO2-emitting actions will have consequences for many millennia," says Timothy Lenton, a professor of climate change and earth systems science at the University of Exeter. "This study suggests those consequences could be much more dramatic than previously expected."
"If we push the Earth system too far," Lenton added, "then it takes over and determines its own response—past that point there will be little we can do about it." [emphasis mine]
image from article
Dr Andrew Glickson points out that, when methane and nitrous oxide are considered, we're above 560 ppm CO2–equivalent. Even ignoring ten other less potent artificial greenhouse gasses, this is enough to collapse the Greenland and West Antarctic Ice sheets, based on paleo data. Assuming a climate sensitivity of 3oC for doubling of CO2, global warming has already potentially reached 3oC rise. Why don't thermometers show that? Because it’s masked by...
… the albedo effects of aerosols, including sulphur dioxide, dust, nitrate and organic carbon...”
... what is happening in the atmosphere-ocean system, accelerating over the last 70 years or so, is an abrupt calamity on a geological dimension, threatening nature and human civilization. [emphasis mine]
Glickson considers the term “climate change“ no longer appropriate. In a sense, I think he means it's like classifying a match and the Dresden firebombing "flames".
As meltwater from Greenland and Antarctica invade nearby oceans, the first effect will be a stadial event. Close proximity of cold surface water and hot equatorial water will produce superstorms.
Roger Hallan explained that in about 30 years, after positive feedbacks have us locked in to this non-future, society will have "a massive nervous breakdown because it’s going to be game over." The public will realize we can't flip the planet back to stability. On our current path, we'll lose the protection of icy poles and get a more uniform global temperature. Instead of a global average of 12.5 oC, Earth's system will flip to an average of 23 oC. There won't be jet streams without the equator-pole temperature gradient, so the oceans will become stagnant and outgass hydrogen sulfide.
I forsee collective madness much sooner than 30 years. How could it take a generation to face climate reality?
Aw, Ruth. do non-futures exist?