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Thank you Ken, that is exactly what I was writing above. The 20s and 30s will see pretty much as much in emissions and likely more warming (due to Arctic feedbacks) as the 10s.

We're currently about 1.2 C (based on five year averages, 2020 was 1.25 C) above the baseline temperature for the IPCC 1.5C Report.  Global temperatures have been increasing by 0.2 C per decade.  With three decades before we get emissions close to net zero, we'll be at 1.8C.

The key is that once we achieve zero emissions, temperatures stabilize and then begin to decrease.  So an overshoot of 1.5C looks likely, but we can keep the temperature increase to under 2.0C.  The IPCC special report on 1.5C published in 2018 outlines the impacts of this temperature range.

Thank you Ken, that is exactly what I was writing above. The 20s and 30s will see pretty much as much in emissions and likely more warming (due to Arctic feedbacks) as the 10s.

Paradigm shifts in science happen slowly.  The current generation of climate scientists have been brought up with the mantra that RCP8.5 equals business as usual. It's only in the past year that the paradigm has begun to shift.

29 January 2020

Emissions – the ‘business as usual’ story is misleading
Stop using the worst-case scenario for climate warming as the most likely outcome — more-realistic baselines make for better policy.

Zeke Hausfather & Glen P. Peters

More than a decade ago, climate scientists and energy modellers made a choice about how to describe the effects of emissions on Earth’s future climate. That choice has had unintended consequences which today are hotly debated. With the Sixth Assessment Report (AR6) from the Intergovernmental Panel on Climate Change (IPCC) moving into its final stages in 2020, there is now a rare opportunity to reboot.

In the lead-up to the 2014 IPCC Fifth Assessment Report (AR5), researchers developed four scenarios for what might happen to greenhouse-gas emissions and climate warming by 2100. They gave these scenarios a catchy title: Representative Concentration Pathways (RCPs)1. One describes a world in which global warming is kept well below 2 °C relative to pre-industrial temperatures (as nations later pledged to do under the Paris climate agreement in 2015); it is called RCP2.6. Another paints a dystopian future that is fossil-fuel intensive and excludes any climate mitigation policies, leading to nearly 5 °C of warming by the end of the century2,3. That one is named RCP8.5.

RCP8.5 was intended to explore an unlikely high-risk future2. But it has been widely used by some experts, policymakers and the media as something else entirely: as a likely ‘business as usual’ outcome. A sizeable portion of the literature on climate impacts refers to RCP8.5 as business as usual, implying that it is probable in the absence of stringent climate mitigation. The media then often amplifies this message, sometimes without communicating the nuances. This results in further confusion regarding probable emissions outcomes, because many climate researchers are not familiar with the details of these scenarios in the energy-modelling literature.

For those making real-life decisions, the choice of scenario becomes important14,16. Emphasizing ways of adapting to an extreme RCP8.5 scenario with around 5 °C warming in 2100 is out of step with the requirement to build resilience and reduce vulnerabilities in the near-term. Most users of climate scenarios care more about the world as it is now, rather than what might have been had global emissions not slowed over the past decade7. Users focused on mitigation are keen to capitalize on emerging opportunities such as cheap renewables, or to avoid overinvesting in stranded assets in dying industries. For example, they want to know whether the rapid cost declines in renewables might make investments in fossil fuels high risk. A RCP8.5 baseline renders these applications useless, because it implies that recent climate policies and technological progress are halted or even reversed.

For policymakers, mitigation policies that depend on the assumptions underlying high-emission baseline scenarios such as RCP8.5 will seem exorbitant, because they do not incorporate the plummeting costs of many low-carbon technologies over the past decade. The marginal investments required to move from 3 °C of warming to well below 2 °C (the main Paris goal) will be much less than moving from 5 °C to well below 2 °C. A narrative of progress and opportunity can make the Paris targets seem feasible, rather than seemingly impossible.

Keep in mind that the chart above was published in January 2020, well before the drop in emissions in 2020 and the new climate commitments made later in the year and just yesterday.  China's stated policy in now to peak by 2030 and be carbon neutral in 2060.  The US stated policy is now to have a carbon free electric grid by 2035 and be carbon neutral by 2050.

RCP 2.6 is now within reach.

Coal India, one of the largest coal producers in the world plans 20 GW of solar. They know whats coming.


Global concentrations of Carbon Dioxide are averaging about 412 ppm, which is in line with the RCP 2.6 scenario.  RCP 8.5 would have the 2020 global average at 415 ppm.
Ken, what counts is CO2eq which is well above 415 ppm. And the main negative force, aerosols, is gonna go down fast if we transition to renewable.

This misunderstanding about CO2eq often pops up on this forum.  CO2eq is a way to take all of the greenhouse gas forcings and combine them into one number.  The IPCC reports take the concentrations of each greenhouse gas and add their forcings.  This is what I showed in the IPCC chart with the individual forcings graphed.

Spikes in temperature due to the decrease of aerosols from the reductions of fossil fuel power sources have been demonstrated to be false.

18 September 2019
Cutting air pollution would not cause ‘near-term spike’ in global warming

A reduction in air pollution brought about by shifting away from fossil fuels would not inadvertently cause a short-term acceleration of global warming, a new study says.

Earlier modelling work using scenarios where fossil-fuel burning ends instantaneously had suggested that a rapid decline in aerosol emissions could remove their cooling impact on the climate and cause a spike in warming.

However, the new study, published in Nature, finds that “even the most aggressive” shift from fossil fuels to clean alternatives to limit warming to 1.5C “provides benefits for climate change mitigation and air quality” at all timescales.

However, there is a key limitation with these studies, says Smith, in that they typically assume an instantaneous removal of all emissions. This is not “realistic in our complex, interdependent world”, he says, which would take much longer to phase out fossil fuels.

In the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC), for example, “frequently asked question 12.3” (pdf) states that “eliminating short-lived negative forcings from sulphate aerosols at the same time (e.g. by air pollution reduction measures) would cause a temporary warming of a few tenths of a degree”.

The accompanying figure (see below) showed this spike in global surface warming (blue dotted line) compared to constant emissions (red) and if the atmospheric concentration of greenhouse gases was held constant at present-day levels (grey).

The model simulations show that, even under the most rapid transition away from fossil fuels, “it takes a good deal of time to actually move the entire planet’s energy systems to clean energy”, says lead author Prof Drew Shindell, professor of earth sciences at Duke University.

The results suggest that, under these more realistic scenarios, “global average temperatures do not show a near-term spike in warming”, the paper says.

While the scenarios show some continued warming in the near term, “none exhibit an acceleration of warming to 0.3C or higher’, the paper says, and “all show a rapid decline in warming rates starting in the 2020s” with some showing cooling by the 2040.

Here's the study referred to in the article:

Shindell, D., Smith, C.J. Climate and air-quality benefits of a realistic phase-out of fossil fuels. Nature 573, 408–411 (2019).


The combustion of fossil fuels produces emissions of the long-lived greenhouse gas carbon dioxide and of short-lived pollutants, including sulfur dioxide, that contribute to the formation of atmospheric aerosols1. Atmospheric aerosols can cool the climate, masking some of the warming effect that results from the emission of greenhouse gases1. However, aerosol particulates are highly toxic when inhaled, leading to millions of premature deaths per year2,3. The phasing out of unabated fossil-fuel combustion will therefore provide health benefits, but will also reduce the extent to which the warming induced by greenhouse gases is masked by aerosols. Because aerosol levels respond much more rapidly to changes in emissions relative to carbon dioxide, large near-term increases in the magnitude and rate of climate warming are predicted in many idealized studies that typically assume an instantaneous removal of all anthropogenic or fossil-fuel-related emissions1,4,5,6,7,8,9. Here we show that more realistic modelling scenarios do not produce a substantial near-term increase in either the magnitude or the rate of warming, and in fact can lead to a decrease in warming rates within two decades of the start of the fossil-fuel phase-out. Accounting for the time required to transform power generation, industry and transportation leads to gradually increasing and largely offsetting climate impacts of carbon dioxide and sulfur dioxide, with the rate of warming further slowed by reductions in fossil-methane emissions. Our results indicate that even the most aggressive plausible transition to a clean-energy society provides benefits for climate change mitigation and air quality at essentially all decadal to centennial timescales.

There are many incorrect assumptions being made about the science and impacts of climate change on this thread.  These often lead to people concluding that we are already doomed, when it is quite clear that the situation has improved dramatically in the past two years and we can limit global warming to well under 2 degrees C.

One of the reasons to keep the temperature increase well under 2 degrees C is that the incidences of loss of the Arctic sea ice decrease from about once per decade at 2 C versus once per century at 1.5 C.

The probability of a sea-ice-free Arctic Ocean5  during summer is substantially higher at 2°C compared to 1.5°C of global warming (medium confidence). Model simulations suggest that at least one sea-ice-free Arctic summer is expected every 10 years for global warming of 2°C, with the frequency decreasing to one sea-ice-free Arctic summer every 100 years under 1.5°C (medium confidence). An intermediate temperature overshoot will have no long- term consequences for Arctic sea ice coverage, and hysteresis is not expected (high confidence). {3.3.8,}

A substantial number of pre-AR5 studies found that there is no indication of hysteresis behaviour of Arctic sea ice under decreasing temperatures following a possible overshoot of a long-term temperature target (Holland et al., 2006; Schröder and Connolley, 2007; Armour et al., 2011; Sedláček et al., 2011; Tietsche et al., 2011; Boucher et al., 2012; Ridley et al., 2012). In particular, the relationship between Arctic sea ice coverage and GMST was found to be indistinguishable between a warming scenario and a cooling scenario. These results have been confirmed by post-AR5 studies (Li et al., 2013; Jahn, 2018), which implies high confidence that an intermediate temperature overshoot has no long-term consequences for Arctic sea ice coverage.

The Jahn, 2018 study addresses both the probabilities of ice-free states and whether they're reversible.

Jahn, A. Reduced probability of ice-free summers for 1.5 °C compared to 2 °C warming. Nature Clim Change 8, 409–413 (2018).


Arctic sea ice has declined rapidly with increasing global temperatures. However, it is largely unknown how Arctic summer sea-ice impacts would vary under the 1.5 °C Paris target compared to scenarios with greater warming. Using the Community Earth System Model, I show that constraining warming to 1.5 °C rather than 2.0 °C reduces the probability of any summer ice-free conditions by 2100 from 100% to 30%. It also reduces the late-century probability of an ice cover below the 2012 record minimum from 98% to 55%. For warming above 2 °C, frequent ice-free conditions can be expected, potentially for several months per year. Although sea-ice loss is generally reversible for decreasing temperatures, sea ice will only recover to current conditions if atmospheric CO2 is reduced below present-day concentrations. Due to model biases, these results provide a lower bound on summer sea-ice impacts, but clearly demonstrate the benefits of constraining warming to 1.5 °C.

Also, China announced a new policy goal to achieve net-zero emissions by 2060.  That means the growth of coal in China will be very limited.  This newspaper article (from the perspective of Australian coal exporters) sums up the future for coal in China very well:

Forget about the trade spat – coal is passé in much of China, and that’s a bigger problem for Australia
January 19, 2021

Australian coal exports to China plummeted last year. While this is due in part to recent trade tensions between Australia and China, our research suggests coal plant closures are a bigger threat to Australia’s export coal in the long term.

China is changing. It’s announced a firm date to reach net-zero emissions, and governments in eastern provinces don’t want polluting coal plants taking up prime real estate. It’s time Australia faced reality, and reconsidered its coal export future.

Coal mining in China mostly occurs in the western provinces. Southeast coastal provinces are largely economically advanced and no longer produce coal. Instead, power stations in those provinces import coal from overseas.

This coal is cheaper than domestic coal, and often easier to access; transport bottlenecks in China often hinder the movement of domestic coal.

Data from monitoring group Global Coal Tracker shows between 2015 and 2019, China closed 291 coal-fired power generation units in power plants of 30 megawatts (MW) or larger, totalling 37 gigawatts (GW) of capacity. For context, Australia decommissioned 5.5 GW of coal-fired power generation units between 2010 and 2017, and currently has 21 GW of coal-fired power stations.

The closures were driven by factors such as climate change and air pollution concern, excess coal power capacity, and China’s move away from some energy-intensive industries.

Second, we found retired coal power stations in China had much shorter lives than the international average. Guangdong, an economically developed region of comparable economic size to Canada, illustrates the point. According to our calculation, the stations in that region had a median age of 15 years at closure. In contrast, coal plants that closed in Australia between 2010 and 2017 had a median age of 43 years.

This suggests coal power stations in China are usually retired not because they’ve reached the end of their productive lives, but rather to achieve a particular purpose.

China’s coal exit is in part due to its strategy to peak its carbon emissions before 2030 and achieve net-zero by 2060. Australia must realistically appraise its coal export prospects in light of the long-term threat posed by shifts in China and other East Asian nations.

A reminder about the assumptions in the RCP scenarios:

Developed just over a decade ago, none of them forecast a major role for wind and solar.  They all assumed that fossil fuels would be cheaper and therefore renewables would play a minor role in the energy mix.

That's no longer true.  In 2018, renewables became cheaper than fossil fuels.  Coal use peaked in 2013 and the number of new coal power plants in the planning stages is less than 100.  It's likely that the last new coal-fired power plant will be built in the next five years and that it won't operate for it's full useful life.

Global concentrations of Carbon Dioxide are averaging about 412 ppm, which is in line with the RCP 2.6 scenario.  RCP 8.5 would have the 2020 global average at 415 ppm.

The politics / Re: Biden’s Presidency
« on: January 20, 2021, 06:29:00 PM »
what a joy to listen to America's poet laurate , Amanda Gorman . b.c.

The politics / Re: Biden’s Presidency
« on: January 20, 2021, 06:27:24 PM »
Amanda Gorman was AWESOME!!!! 🙂

The politics / Re: Biden’s Presidency
« on: January 19, 2021, 10:24:29 PM »
mitch mconnell: Capitol hill mob was 'provoked' by trump

See trump it sucks to be thrown in front of a bus by your allies. It is not like you came up with the idea but most people are more strategic about it. mconnell waited until you were no longer usefull to him instead of letting his ego make the decision. Hope to see you in prison soon.

People tend to forget that renewables are now cheaper than fossil fuels.  In fact, in the US, power utilities can build new renewable power plants and shut down operating coal power plants and save money doing so.  Most of the coal-fired power plants operating in the US wont be by 2030. 

The rest of the world is in a similar situation.  Since renewables only became cheaper than fossil fuels in the past two years, the manufacturing plants needed to scale up solar and wind production are still in the planning stages.  However, global solar panel manufacturing capacity is set to increase exponentially in the next few years.

The energy transition is well underway.  The Covid recession stole the headlines last year, but the coal industry is on it's last legs and the oil and gas industry are starting to recognize that oil demand has peaked and natural gas peak demand is imminent.

In the US, the Biden administration is poised to reverse the policy changes implemented by the Trump administration within the first few days in office.  The new stimulus package to be enacted this spring will include many measures to address climate change.  And the new cabinet secretaries who will be taking office soon are in favor of many climate-friendly policies, from regenerative agriculture to shifting oil-service industries into geothermal energy.

And China recently announced it's policy to go carbon neutral by 2060.  The new five-year plan to be introduced this spring will include energy investments with that policy in place.  This winter, they've greatly curtailed coal use even though parts of the country are suffering blackouts in freezing weather.  They will be able to use their great head start in solar panel manufacturing to address the gaps in their power system.

Is there not research indicating that the key is energy imbalance, and even if Global warming stopped how long before the energy imbalance returned to zero?
Is there not also a question of unhelpful changes to land and ocean carbon sinks, including some sinks becoming carbon emitters?

And anyway, if they are right we will just have to rely on all the other stuff humankind does to continue to successfully trash the planet.

>unhelpful changes to land and ocean carbon sinks

With land, if the CO2 stops going up, there isn't much inertia in the system. Tree live a long time but if atmospheric levels of CO2 are not going up why would trees continue to take up more? I believe land sinks would fall to practically nil over just 5 years or so.

However the ocean is a bigger sink than land. Surface water gets into balance with atmosphere in a few months so this sink also disappears quickly. However with 1000 year overturning circulation new water comes to surface which for next 500-1000 years has low levels of dissolved CO2. So there is a much bigger difference between CO2 it has dissolved and the equilibrium level compared to surface waters which were in equilibrium at last years level of atmospheric CO2.

So this part of the sinks remains for quite some time even if other parts of the sinks should be expected to disappear quickly. Temperature rises do of course cause new sources but I believe I would suggest that so far these new sources have been small compared to the sinks. Yes there is some risk here that while these new sources may be small they might grow and continue for a long period unless the temperature goes down quite markedly soon.

Anyway if we get our emissions to net zero then I think the conclusion that CO2 levels will fall will be fairly robust.

If we struggle to reduce our net emissions to 20% of current levels then it will be much less clear whether there will be a (fall or) short term stabilisation of CO2 levels.

Unlikely to be adequate as an eventual target, but it might buy more time to work out how to do further cuts in net emissions.

80% cut in net emissions is a very tough target to reach let alone 100% but anything that helps should be welcomed rather than dismissing as non-sense because we prefer a "we're all doomed" commentary.

Policy and solutions / Re: Renewable Energy
« on: December 22, 2020, 08:46:45 PM »
The stimulus bill passed by the US Congress yesterday includes many provisions to spur the investment in renewables and other green energy technologies.

Stimulus deal includes raft of provisions to fight climate change
The most substantial federal investment in green technology in a decade includes billions for solar, wind, battery storage and carbon capture. Congress also agreed to cut the use of HFCs, chemicals used in refrigeration that are driving global warming.
By Sarah Kaplan and Dino Grandoni
Dec. 21, 2020

In one of the biggest victories for U.S. climate action in a decade, Congress has moved to phase out a class of potent planet-warming chemicals and provide billions of dollars for renewable energy and efforts to suck carbon from the atmosphere as part of the $900 billion coronavirus relief package.

It will cut the use of hydrofluorocarbons (HFCs), chemicals used in air conditioners and refrigerators that are hundreds of times worse for the climate than carbon dioxide. It authorizes a sweeping set of new renewable energy measures, including tax credit extensions and new research and development programs for solar, wind and energy storage; funding for energy efficiency projects; upgrades to the electric grid and a new commitment to research on removing carbon from the atmosphere. And it reauthorizes an Environmental Protection Agency program to curb emissions from diesel engines.

The HFC measure, which empowers the EPA to cut the production and use of HFCs by 85 percent over the next 15 years, is expected to save as much as half a degree Celsius of warming by the end of the century. Scientists say the world needs to constrain the increase in the average global temperature to less than 2 degrees Celsius compared with preindustrial times to avoid catastrophic, irreversible damage to the planet. Some places around the globe are already experiencing an average temperature rise beyond that threshold.

Included in the energy package are roughly $4 billion for solar, wind, hydropower and geothermal research and development; $1.7 billion to help low-income families install renewable energy sources in their homes; $2.6 billion for the Energy Department’s sustainable transportation program; and $500 million for research on reducing industrial emissions.

In a boon for renewable energy companies, Congress extended tax credits for wind and solar and introduced a new credit for offshore wind projects, which Heather Zichal, chief executive of the American Clean Power Association, called “America’s largest untapped clean energy source.” One Department of Energy analysis suggested that developing just 4 percent of the total U.S. offshore wind capacity could power some 25 million homes and reduce the nation’s greenhouse gas emissions by almost 2 percent.

Permafrost / Re: Arctic Methane Release
« on: December 14, 2020, 08:05:35 PM »
The Moon Controls the Release of Methane in Arctic Ocean

Small pressure changes affect methane release. A recent paper in Nature Communications even implies that the moon has a role to play.

The moon controls one of the most formidable forces in nature—the tides that shape our coastlines. Tides, in turn, significantly affect the intensity of methane emissions from the Arctic Ocean seafloor.

"We noticed that gas accumulations, which are in the sediments within a meter from the seafloor, are vulnerable to even slight pressure changes in the water column. Low tide means less of such hydrostatic pressure and higher intensity of methane release. High tide equals high pressure and lower intensity of the release," says co-author of the paper Andreia Plaza Faverola.

"It is the first time that this observation has been made in the Arctic Ocean. It means that slight pressure changes can release significant amounts of methane.

Plaza Faverola points out that the observations were made by placing a tool called a piezometer in the sediments and leaving it there for four days.

It measured the pressure and temperature of the water inside the pores of the sediment. Hourly changes in the measured pressure and temperature revealed the presence of gas close to the seafloor that ascends and descends as the tides change. The measurements were made in an area of the Arctic Ocean where no methane release has previously been observed but where massive gas hydrate concentrations have been sampled.

"This tells us that gas release from the seafloor is more widespread than we can see using traditional sonar surveys. We saw no bubbles or columns of gas in the water. Gas burps that have a periodicity of several hours won't be identified unless there is a permanent monitoring tool in place, such as the piezometer," says Plaza Faverola

These observations imply that the quantification of present-day gas emissions in the Arctic may be underestimated. High tides, however, seem to influence gas emissions by reducing their height and volume.

"What we found was unexpected and the implications are big. This is a deep-water site. Small changes in pressure can increase the gas emissions but the methane will still stay in the ocean due to the water depth. But what happens in shallower sites? This approach needs to be done in shallow Arctic waters as well, over a longer period. In shallow water, the possibility that methane will reach the atmosphere is greater," says Knies

... The question remains whether sea-level rise due to global warming might partially counterbalance the effect of temperature on submarine methane emissions.

Nabil Sultan et al, Impact of tides and sea-level on deep-sea Arctic methane emissions, Nature Communications (2020).

Permafrost / Re: Arctic Methane Release
« on: December 02, 2020, 03:52:35 AM »
Kassy, so I had a think about this, and tried to come up with sites that are more likely to have increased in methane faster than the global average.
I tried Niwot Ridge, Colorado, United States (NWR) due to the local fracking activity and Mt. Waliguan, Peoples Republic of China (WLG) due to increased rice production and increased industrial activity. I don't have any local knowledge of these places, so it was a bit of a guess.

There is a slight increased trend on both sites vs south pole data. While the trend for Barrow  (BRW) is flat.

Now I did deliberately pick these sites because I thought would have the largest increase in emissions. But then I originally expected to see the same trend in Barrow and Tiksi and didn't find it.

I'm no expert on this, so I'm happy for any challenge of these methods.

Permafrost / Re: Arctic Methane Release
« on: November 30, 2020, 02:51:09 PM »
I was curious to see if the methane concentrations in the arctic, especially around the East Siberian Arctic Shelf, were increasing any faster than the rest of the world.

Turns out it's not.

Using the NOAA average monthly flask data from Tiksi (for the relatively short time it was running),
 comparing to Barrow, Mona Loa, and Antarctic. Looking at the difference between the sites.
And over a longer term, looking at the difference between Barrow and Mona Loa, and Antarctic.

Permafrost / Re: Arctic Methane Release
« on: November 16, 2020, 02:51:29 AM »
Welcome ArgonneForest.

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