Arctic Methane Emissions ‘Certain to Trigger Warming’

[ScienceRocks]

A new international study offers a worrisome answer to the question of why global levels of methane — one of the most potent heat-trapping greenhouse gases — have begun rising again in recent years.

The study, “A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands,” finds that the rise “likely stems from wetland emissions.”


The news here is that while scientists had thought methane emissions from the wetlands would be largest in the tropics, in fact northern wetlands (such as the fens, Canada’s most common form of wetland) are also major contributors, as the 19-author study concludes. The lead author, Canadian Prof. Merritt Turetsky, explained:

“But our analyses show that northern fens, such as those created when permafrost thaws, can have emissions comparable to warm sites in the tropics, despite their cold temperatures … Not only are fens one of the strongest sources of wetland greenhouse gases, but we also know that Canadian forests and tundra underlain by permafrost are thawing and creating these kinds of high methane-producing ecosystems.”

This is exceedingly worrisome for three reasons. First, the permafrost contains twice as much carbon as the atmosphere does today. Second, the Intergovernmental Panel on Climate Change (IPCC) reported last year that methane (CH4) is a far more potent greenhouse gas than we had previously realized — a stunning 86 times more potent than carbon dioxide over a 20-year time frame. Third, since warming permafrost releases methane that in turn increases the rate of global warming, this process represents a positive or amplifying carbon cycle feedback.

Turetsky noted:

The permafrost carbon feedback is one of the important and likely consequences of climate change, and it is certain to trigger additional warming … Instead of reducing emissions, we currently are on track with the most dire scenario considered by the IPCC.

So permafrost thawing is “certain to trigger additional warming” — and yet the super-conservative IPCC modelers ignored any warming impact from the permafrost! This in spite of the fact that the IPCC itself concluded in its recent assessment of climate science:

It is virtually certain that near-surface permafrost extent at high northern latitudes will be reduced as global mean surface temperature increases. By the end of the 21st century, the area of permafrost near the surface (upper 3.5 m) is projected to decrease by between 37% (RCP2.6) to 81% (RCP8.5) for the model average.

While the IPCC modelers failed to incorporate this catastrophic loss of the top ten feet of permafrost, other researchers didn’t. One major 2012 study found that the carbon feedback alone from thawing permafrost will add up to 1.5°F to total global warming by 2100.

This new research is yet more evidence that given our do-little path climate policy, we are headed towards 10°F warming compared to preindustrial levels, which is terra incognita for terra firma and its inhabitants.

Is This Why Heat-Trapping Methane Emissions Are On The Rise? | ThinkProgress

 

[ScienceRocks]

Abstract

Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature, water table, and vegetation, but also show that these relationships are modified depending on wetland type (bog, fen, or swamp), region (subarctic to temperate), and disturbance. Fen methane flux was more sensitive to vegetation and less sensitive to temperature than bog or swamp fluxes. The optimal water table for methane flux was consistently below the peat surface in bogs, close to the peat surface in poor fens, and above the peat surface in rich fens. However, the largest flux in bogs occurred when dry 30-day averaged antecedent conditions were followed by wet conditions, while in fens and swamps, the largest flux occurred when both 30-day averaged antecedent and current conditions were wet. Drained wetlands exhibited distinct characteristics, e.g. the absence of large flux following wet and warm conditions, suggesting that the same functional relationships between methane flux and environmental conditions cannot be used across pristine and disturbed wetlands. Together, our results suggest that water table and temperature are dominant controls on methane flux in pristine bogs and swamps, while other processes, such as vascular transport in pristine fens, have the potential to partially override the effect of these controls in other wetland types. Because wetland types vary in methane emissions and have distinct controls, these ecosystems need to be considered separately to yield reliable estimates of global wetland methane release.

A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands - Turetsky - 2014 - Global Change Biology - Wiley Online Library

 

[IanC]

the methane projections by the IPCC, and used in climate models, are wildly exaggerated. this is one of the reasons why temperature predictions are so much higher than reality.

 

[Crick]

From Chapter 10.4.3 of WGI of AR4:

Recent measurements show that CH4 growth rates have declined and were negative for several years in the early 21st century (see Section 2.3.2). The observed rate of increase of 0.8 ppb yr–1 for the period 1999 to 2004 is considerably less than the rate of 6 ppb yr–1 assumed in all the SRES scenarios for the period 1990 to 2000 (Nakićenović and Swart, 2000; TAR Appendix II). Recent studies (Dentener et al., 2005) have considered lower emission scenarios (see above) that take account of new pollution control techniques adopted in major developing countries. In the CLE scenario, emissions of CH4 are comparable to the B2 scenario and increase from 340 Tg yr–1 in 2000 to 450 Tg yr–1 in 2030. The CH4 concentrations increase from 1,750 ppb in 2000 to between 2,090 and 2,200 ppb in 2030 under this scenario. In the MFR scenario, the emissions are sufficiently low that the concentrations in 2030 are unchanged at 1,750 ppb. Under these conditions, the changes in radiative forcing due to CH4 between the 1990s and 2020s are less than 0.01 W m–2.

Current understanding of the magnitude and variation of CH4 sources and sinks is covered in Section 7.4, where it is noted that there are substantial uncertainties although the modelling has progressed. There is some evidence for a coupling between climate and wetland emissions. For example, calculations using atmospheric concentrations and small-scale emission measurements as input differ by 60% (Shindell and Schmidt, 2004). Concurrent changes in natural sources of CH4 are now being estimated to first order using simple models of the biosphere coupled to AOGCMs. Simulations of the response of wetlands to climate change from doubling atmospheric CO2 show that wetland emissions increase by 78% (Shindell and Schmidt, 2004). Most of this effect is caused by growth in the flux of CH4 from existing tropical wetlands. The increase would be equivalent to approximately 20% of current inventories and would contribute an additional 430 ppb to atmospheric concentrations. Global radiative forcing would increase by approximately 4 to 5% from the effects of wetland emissions by 2100 (Gedney et al., 2004).
********************************************************

Unlike denier/pseudo-science, real science admits mistakes and looks for explanations.

 

[CrusaderFrank]

An excellent video, up to date, and accurate. Unfortunately, I think that the worst case is what will play out.

The worst case is listening to people who won't do real science and expect something good to come of it

 

[Crick]

Damn Matty you're even worse at this than at hating black people

I don't hate black people. At all!

I just point out the double standard society has against whites and how blacks get away with things.

I bet they'd get away with less things if you got your hood and robe out of the closet. Burn a few crosses on a few lawns. That'll learn 'em. Right? Or do you think we just need to use the legal system to make sure they don't get away with their crimes. More convictions. Harder punishments. Less white people's money spent feeding those lazy pickaninny welfare brats. Right? Right?

 

[editec]

So much deflection, so much denial.

Not one single attempt to refute the science.

 

[Old Rocks]

An excellent video, up to date, and accurate. Unfortunately, I think that the worst case is what will play out.

The worst case is listening to people who won't do real science and expect something good to come of it

Such as you.

You never present anything other than flap-yap, and have yet to post a credible site dealing with science in any aspect.

 

[Old Rocks]

From Chapter 10.4.3 of WGI of AR4:

Recent measurements show that CH4 growth rates have declined and were negative for several years in the early 21st century (see Section 2.3.2). The observed rate of increase of 0.8 ppb yr–1 for the period 1999 to 2004 is considerably less than the rate of 6 ppb yr–1 assumed in all the SRES scenarios for the period 1990 to 2000 (Nakićenović and Swart, 2000; TAR Appendix II). Recent studies (Dentener et al., 2005) have considered lower emission scenarios (see above) that take account of new pollution control techniques adopted in major developing countries. In the CLE scenario, emissions of CH4 are comparable to the B2 scenario and increase from 340 Tg yr–1 in 2000 to 450 Tg yr–1 in 2030. The CH4 concentrations increase from 1,750 ppb in 2000 to between 2,090 and 2,200 ppb in 2030 under this scenario. In the MFR scenario, the emissions are sufficiently low that the concentrations in 2030 are unchanged at 1,750 ppb. Under these conditions, the changes in radiative forcing due to CH4 between the 1990s and 2020s are less than 0.01 W m–2.

Current understanding of the magnitude and variation of CH4 sources and sinks is covered in Section 7.4, where it is noted that there are substantial uncertainties although the modelling has progressed. There is some evidence for a coupling between climate and wetland emissions. For example, calculations using atmospheric concentrations and small-scale emission measurements as input differ by 60% (Shindell and Schmidt, 2004). Concurrent changes in natural sources of CH4 are now being estimated to first order using simple models of the biosphere coupled to AOGCMs. Simulations of the response of wetlands to climate change from doubling atmospheric CO2 show that wetland emissions increase by 78% (Shindell and Schmidt, 2004). Most of this effect is caused by growth in the flux of CH4 from existing tropical wetlands. The increase would be equivalent to approximately 20% of current inventories and would contribute an additional 430 ppb to atmospheric concentrations. Global radiative forcing would increase by approximately 4 to 5% from the effects of wetland emissions by 2100 (Gedney et al., 2004).
********************************************************

Unlike denier/pseudo-science, real science admits mistakes and looks for explanations.

The problem here is we have never been down this path before. We really don't know how fast the Permafrost will thaw, we don't fully understand what the effects will be. We do know that there will be emissions of CO2 and CH4, but not the ratio or rate of the emissions. And then there are the Arctic Ocean clathrates. Particulary on the East Siberian Shelf.

Those that say ignore all of this are betting the farm on things remaining the same. At the very time we are seeing major changes in the Arctic. A rapidly increasing rate of ice flow off of Greenland, a warming Arctic Ocean, and the Arctic Sea Ice in a death spiral.

 

[dilloduck]

From Chapter 10.4.3 of WGI of AR4:

Recent measurements show that CH4 growth rates have declined and were negative for several years in the early 21st century (see Section 2.3.2). The observed rate of increase of 0.8 ppb yr–1 for the period 1999 to 2004 is considerably less than the rate of 6 ppb yr–1 assumed in all the SRES scenarios for the period 1990 to 2000 (Nakićenović and Swart, 2000; TAR Appendix II). Recent studies (Dentener et al., 2005) have considered lower emission scenarios (see above) that take account of new pollution control techniques adopted in major developing countries. In the CLE scenario, emissions of CH4 are comparable to the B2 scenario and increase from 340 Tg yr–1 in 2000 to 450 Tg yr–1 in 2030. The CH4 concentrations increase from 1,750 ppb in 2000 to between 2,090 and 2,200 ppb in 2030 under this scenario. In the MFR scenario, the emissions are sufficiently low that the concentrations in 2030 are unchanged at 1,750 ppb. Under these conditions, the changes in radiative forcing due to CH4 between the 1990s and 2020s are less than 0.01 W m–2.

Current understanding of the magnitude and variation of CH4 sources and sinks is covered in Section 7.4, where it is noted that there are substantial uncertainties although the modelling has progressed. There is some evidence for a coupling between climate and wetland emissions. For example, calculations using atmospheric concentrations and small-scale emission measurements as input differ by 60% (Shindell and Schmidt, 2004). Concurrent changes in natural sources of CH4 are now being estimated to first order using simple models of the biosphere coupled to AOGCMs. Simulations of the response of wetlands to climate change from doubling atmospheric CO2 show that wetland emissions increase by 78% (Shindell and Schmidt, 2004). Most of this effect is caused by growth in the flux of CH4 from existing tropical wetlands. The increase would be equivalent to approximately 20% of current inventories and would contribute an additional 430 ppb to atmospheric concentrations. Global radiative forcing would increase by approximately 4 to 5% from the effects of wetland emissions by 2100 (Gedney et al., 2004).
********************************************************

Unlike denier/pseudo-science, real science admits mistakes and looks for explanations.

The problem here is we have never been down this path before. We really don't know how fast the Permafrost will thaw, we don't fully understand what the effects will be. We do know that there will be emissions of CO2 and CH4, but not the ratio or rate of the emissions. And then there are the Arctic Ocean clathrates. Particulary on the East Siberian Shelf.

Those that say ignore all of this are betting the farm on things remaining the same. At the very time we are seeing major changes in the Arctic. A rapidly increasing rate of ice flow off of Greenland, a warming Arctic Ocean, and the Arctic Sea Ice in a death spiral.

Those that are ignoring this know that there is nothing that can be done about whatever scary thing science is drumming up this time.

 

[Crick]

Does that include you?

 

[Kosh]

CO2 nor methane drives climate...