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Science / Re: Carbon Cycle

« on: November 03, 2020, 07:13:24 AM »

For 2°C:

Can 232 GtC (851 CO2) of soil carbon be used to update remaining carbon budgets in SR15, Ch 2, Table 2.2?

For 50% chance in Table 2.2, budget to keep below 2°C is 1500 GtCO2 (less Earth System Feedbacks less emissions since 1/1/2018).

Taking 851 from 1500 gives 650 GtCO2 (less Earth System Feedbacks less emissions since)

Earth system feedbacks include CO2 released by permafrost thawing or methane released by wetland. These in Table 2.2 given as 100 GtCO2 for  a 1.5°C rise, but will  be more for 2°C rise.
Guess 150GtCO2?

Emissions since date in SR15 (1/1/2018) about 100 GtCO2?

That gives remaining carbon budget of 650-150-100 = 400 Gt CO2.

That's a remaining budget of 53 tonnes CO2 per human for 2°C rise.

Crude but this it at all realistic?

How much does non-CO2 climate forcing reduce this?

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Arctic sea ice / Re: The 2020/2021 freezing season

« on: November 02, 2020, 05:13:25 AM »

Is this relevant here?




From http://marineheatwaves.org

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Policy and solutions / Re: Methane emissions, sea levels and temperature

« on: July 13, 2020, 08:51:03 PM »

Just posted: Cut methane emissions soon, Sea level, methane and a false assumption

I'd still like to know if anyone agrees/disagrees.

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Policy and solutions / Re: Methane emissions, sea levels and temperature

« on: July 12, 2020, 02:01:20 PM »

I'm trying to write a piece for my blog about the lack of appreciation of this problem.

Methane's heating effect on sea-level is very different to its effect on global temperature.
It is much more worrying.

I think it's unknown to many, especially policy makers.

Am I wrong?

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Policy and solutions / Re: Methane emissions, sea levels and temperature

« on: July 11, 2020, 01:35:19 AM »

Kassy, Thanks I meant to follow up with references but got distracted.


Methane forcing is 58% of CO2 forcing calculated from numbers in Figure SPM.5
IPCC AR5, WG1,Summaryfor Policymakers

Methane has ... a half life of 9.1 years
Wikipedia

Ocean warming dominates the increase in energy stored in the climate system, accounting
for more than 90% of the energy accumulated between 1971 and 2010 (high confidence).

IPCC AR5, WG1,Summaryfor Policymakers

It is very likely that there is a substantial anthropogenic contribution to the global mean sea level rise since the 1970s. This is based on the high confidence in an anthropogenic influence on the two largest contributions to sea level rise, that is thermal expansion and glacier mass loss.

IPCC AR5, WG1,Summaryfor Policymakers

Also ...

Centuries of thermal sea-level rise due to anthropogenic emissions of short-lived greenhouse gases.

Increased importance of methane reduction for a 1.5 degree target

Very Strong Atmospheric Methane Growth in the 4 Years 2014–2017: Implications for the Paris Agreement

Am I right in thinking that it is commonly believed that limiting GMST is THE means of limiting sea level rise - and as methane is less important for peak GMST, it can't be important for sea level?

This belief is surely false.

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Science / Re: 2020 Mauna Loa CO2 levels

« on: March 18, 2020, 07:37:00 AM »

Coronavirus and atmospheric concentrations of CO2

Scripps Oceanography geochemist Ralph Keeling said fossil fuel use would have to decline by about 10 percent around the world and would need to be sustained for a year to show up clearly in carbon dioxide levels.

History has shown that carbon dioxide levels typically resume their climb quickly as normal economic activity rebounds. If there is any benefit of the coronavirus event in terms of slowing the pace of climate change, it could be the changing of people’s travel and work habits in ways that lead to sustained reductions in fossil fuel use. Only those kinds of long-term systemic reductions will change the trajectory of carbon dioxide levels in the atmosphere, Keeling said.

What does it take for the coronavirus (or other major economic events) to affect global carbon dioxide readings?

-----

However, UK emissions of CO2 have remained lower after 2007/2008 crash.


UK's carbon footprint.

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Policy and solutions / Re: Cars, cars and more cars Part Deux

« on: February 07, 2020, 08:11:38 PM »

gerontocrat, that's good.

If they reject cars, they should be able to live in decent cities, towns and villages that are suited to them.

That is cities, towns and villages without cars.

They are so much cheaper and pleasanter and don't screw the climate.

For and economist-friendly note, see The parable of the smoking carriages.

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Policy and solutions / Re: Cars, cars and more cars Part Deux

« on: February 07, 2020, 06:57:05 PM »

NeilT

Our societies have reorganised themselves around the reality of pervasive personal transport.

Environment Commissioner Ripa di Meana got the sack for commissioning a report which showed that car-free living is very much cheaper. It's obviously much pleasanter.

If we do the sums, we really are left with the choice

Cars to drive or planet to live in.

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Policy and solutions / Re: Cars, cars and more cars Part Deux

« on: February 06, 2020, 11:44:36 PM »

In IPCC SR15, there is a discussion of the Shared Socio-Economic Pathways (SSPs), which create estimates of greenhouse gas emissions from different assumptions about the way we might change aspects of our lives.

These estimates of emissions can be tested with climate models to see how the climate goals of the Paris Agreement might be be met.

SR15 says

outright reductions in travel demand (e.g., as a result of integrated transport, land-use and urban planning), figure much less prominently.

Does this mean the authors of the SSPs have not dared ask us to give up our cars?

Cars have carbon footprints that soon exceed remaining carbon budgets.

Surely this means:

We can have cars to drive or a planet to live in.

But not both.

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Consequences / Re: Wildfires

« on: August 27, 2019, 04:21:02 PM »

I've been trying to find out whether increased wildfires are in the CMIP models
account for forest fire feedbacks. I wrote Carbon Footprints & Wildfires just before the Amazon Headlined.

My latest score is

.

Corrections and improvements welcome.

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Greenland and Arctic Circle / Re: What's new in Greenland?

« on: July 08, 2019, 08:39:50 PM »

Is this sand from Greenland the right sort of sand?

Is the world running out of sand?

Builders like angular sand of the kind found on riverbeds. Sand, sand everywhere, nor any grain to use, to paraphrase Coleridge. A textbook example is the Burj Khalifa in Dubai, the world’s tallest skyscraper. Despite being surrounded by sand, it was constructed with concrete incorporating the “right kind of sand” from Australia.

High buildings have high embodied carbon.
Let's build low wooden ones.

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Policy and solutions / Re: UN Climate Agreement - Paris 2015 and beyond

« on: September 07, 2018, 12:14:25 AM »

"EIA has great data this morning:
1) 2017 carbon emissions down 0.9%;
2) 2017 emissions 14% below 2005 levels;
3) Total carbon emissions from gas higher than coal;
4) Petroleum top emitter, responsible for 46% of total emissions.”
https://mobile.twitter.com/johnrhanger/status/1037323456226967552

Are methane leaks properly estimated and counted ?
"Methane emissions of this magnitude, per unit of natural gas consumed, produce radiative forcing over a 20-year time horizon comparable to the CO2 from natural gas combustion" So not really much progress in the power sector. http://science.sciencemag.org/content/early/2018/06/20/science.aar7204

Are "imported" emissions counted?
"One-quarter of all global greenhouse gas emissions are caused by the manufacture of products destined for export – and are not accounted for in most nations’ climate policies." https://buyclean.org/media/2016/12/buyclean-execsummary-082718.pdf

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Policy and solutions / Re: Cars, cars and more cars. And trucks, and....

« on: August 29, 2018, 06:03:28 PM »

bluesky

do you have numbers regarding the average carbon footprint of a motorist, and by EU countries (mainly UK, France, Germany, Spain, Italy)? and what is the car emission share within the overall carbon footprint of an average citizen?

That's an interesting piece of homework you have set me. I can't answer it easily. I might try more seriously in due course. But here is some fragments:

1. CO2 from driving a car is often given in gms CO2 per km. These are tailpipe emissions and don't include the CO2 emitted in extracting, processing and transporting the fuel. I picked up a figure of 10% for this somewhere. So for these cars, I have made these estimates using emissions data from the Department for Transport and UK average car miles from Drivers' annual mileage rates drop to new low.



2) The CO2 from manufacturing a car is large. These figures come form Mike Berners Lee in What's the carbon footprint of ... a new car? and Average age of cars on the road in the United Kingdom (UK) between 2000 and 2016*:



3) The combined result, which is dependent on assumptions you can see above, is:



However, having a car is an indicator of affluence and there is a relationship between car ownership and affluence as the Stockholm Environment Institute noted in their report on Derwenthorpe:

the richest 10 per cent of households nationally consuming three times more carbon for household energy and travel than the poorest 10 per cent.

One consideration is that they tend to live in places that require more daily travel but there are many other reasons. Worldwide it's the affluent that are ruining the climate as this Oxfam infographic shows:



Clearly, more work needed but I feel confident that building new homes for motorists is contrary to UN Resolution 42/187 and so it is now against planning regulations in the UK.

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Antarctica / Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)

« on: November 24, 2017, 05:41:12 PM »

Was the article by Holthaus this one on grist?

It was criticised by Tamsin Edwards in the Guardian e.g.

But Eric is wrong to say Antarctica’s ‘ice budget’ has tipped out of balance due to our burning of fossil fuels. Not only has it been out of balance before – such as the ancient West Antarctic collapse that causes concern – but the reason for the Amundsen Sea changes, where most ice is being lost, is that the ring of deep warm water around Antarctica has welled up onto the continental shelf and is melting the ice from underneath. We don’t know if human activities made this more likely.

Any comments?

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