“Globally we emit around 40 billion tonnes of CO₂ annually, so net zero CO₂ by
2050 will require CO₂ removal of this scale, starting immediately.”
Not quite. Net Zero requires that carbon removal equal total emissions. While
the primary focus of the IPCC remains reducing total emissions, the hope is
that the NET task could be smaller if emissions can be cut.
Unfortunately, all the emission trends seem to be in the wrong direction, so it
looks like the NET task will actually be bigger. As well, the equation must
include CO2 equivalents. The IPCC projections are that by 2030 total CO2e
emissions will be 60 billion tonnes (gigatons or GT) under Business as Usual,
and that full implementation of the Paris Accord would cut that by 10% to 54 GT
(New York Times 6 Nov 2017, World Emissions Far Off Course).
Therefore, the projected task for NETs to achieve net zero is to remove 54 GT
of CO2e annually by 2030, unless emissions come down faster than agreed at
Paris.
Further to this massive task, climate restoration requires an even bigger goal.
In order to steer the planet away from the hothouse precipice, NETs should aim
to remove double total emissions, 100 GT. And in the meantime, solar radiation
management should be deployed to help avoid unforeseen dangerous tipping
points. These are the primary planetary security problems.
Robert Tulip
From: Andrew Lockley <andrew.lock...@gmail.com>
To: geoengineering <geoengineering@googlegroups.com>;
"carbondioxideremo...@googlegroups.com <carbondioxideremo...@googlegroups.com>"
<carbondioxideremo...@googlegroups.com>
Sent: Tuesday, 11 December 2018, 4:47
Subject: [CDR] COP24: here's what must be agreed to keep warming at 1.5°C
Poster's note: mass media, but respected author and topical
https://theconversation.com/amp/cop24-heres-what-must-be-agreed-to-keep-warming-at-1-5-c-107968?__twitter_impression=true
COP24: here's what must be agreed to keep warming at 1.5°CHugh Hunt, University
of CambridgeDecember 3, 2018 11.12am GMTThe Paris Agreement of 2015 has a
central aim to keep global temperature rise this century well below 2°C above
pre-industrial levels and to “pursue efforts” to limit the temperature increase
even further to 1.5°C. This is an ambitious aim – global temperatures are
rapidly approaching the 1.5°C target and the 2°C limit is not far away.
The path to 1.5°C requires that the world achieve zero emissions before 2050.
It is imperative, therefore, that we stop burning fossil fuels, known as
mitigation. However, our present trajectory suggests we’re not on track. COP24
can’t take its eye off this ball –- there is no long-term plan that doesn’t
include zero fossil-carbon emissions. The scientific consensus is that we need
to reach “net zero” CO₂ emissions by 2050. But to tack closer to a scenario of
1.5°C warming, COP24 should set this target for 2035.
Black, observed temperatures; blue, probable range from decadal forecasts; red,
retrospective forecasts; green, climate simulations of the 20th century. The
Met OfficeCarbon removal and non-CO₂ emissionsThe United Nations, in the IPCC
Special Report on Global Warming of 1.5ºC has accepted that there isn’t any
obvious pathway to zero emissions in such a short time frame, so they have
pegged their hopes on NETs – Negative Emissions Technologies. These approaches
include carbon capture and storage (CCS), which involves sucking CO₂ from the
air and storing it deep underground.
Carbon removal along these lines is the second imperative for COP24 in
Katowice. Globally we emit around 40 billion tonnes of CO₂ annually, so net
zero CO₂ by 2050 will require CO₂ removal of this scale, starting immediately.
But CO₂ isn’t the only problem. We emit other greenhouse gases such as methane,
nitrous oxide and chlorofluorocarbons (CFCs) which all contribute to climate
change. Methane is on the rise and is 84 times more potent as a greenhouse gas
than CO₂.
It comes from cows, and it leaks from oil wells and coal mines as “fugitive
methane”. It is also seeping out of the melting permafrost in the Arctic. This
is a worrying form of “positive feedback” where global warming causes the
further release of gases that cause further warming.
Nitrous Oxide, which is 300 times more potent than CO₂, is rising too, caused
by modern agriculture. And the concentration of refrigerant gases, such as
CFCs, which are thousands of times more potent than CO₂, is not falling as fast
as we’d hoped. So COP24 has a third imperative, to prevent the rise of non-CO₂
greenhouse gases. If we can stabilise non-CO₂ greenhouse emissions at present
day levels we’ll be doing well, but concentrations are rising fast.
Limiting warming to 1.5°C or 2°C requires mitigation (energy efficiency and
renewable generation) and CO₂ removal. MCCDesperate times, desperate
measuresAll of this is going to be hard work. We’re failing to cut down our
emissions, the technologies for NETs don’t exist at any meaningful scale, yet
and there are no political drivers in place to enforce their deployment. There
is also a real risk of a dramatic rise in methane in the near future. COP24
will have to consider emergency plans.
One such plan is very controversial. There are so-called “geoengineering”
technologies which can be used to cause changes in global temperatures. One of
these is Solar Radiation Management (SRM), which involves injecting tiny
aerosol particles high in the atmosphere where they reflect sunlight into space.
We know from the eruption of Mount Pinatubo in 1991 that stratospheric aerosols
caused a cooling of around 1°C over a year. The northern winter of 1992 saw a
dramatic increase in sea ice and a stalling of glacial melting. SRM
technologies exist and the first sun-dimming experiments are underway.
A proposed SRM technique which would inject sulphate aerosols into the
atmosphere. Hugh Hunt/Wikimedia CommonsThere is a realistic possibility that
deploying SRM can buy us some time to enact the essential measures needed to
stop warming at or before 1.5°C. The discussions at COP24 must keep all options
on the table, and as unpalatable as geoengineering technologies might seem,
their deployment may prove to be unavoidable.
The indicators are all in the danger zone. We are seeing increasing Arctic
temperatures, rapid loss of Arctic sea ice, reduced Arctic reflectivity,
rapidly melting ice shelves and methane release from permafrost. These are
leading to rapidly rising sea levels, coastal flooding and storm surges,
increased hurricane and storm activity, dry and hot conditions conducive to
wildfires, and drought and crop failure.
The urgency for decisive action is the imperative for COP24. The UN must press
on with four major strands for meeting the Paris 1.5°C target:
Reduce fossil carbon emissions.
Remove carbon from the atmosphere (NETs).
Halt the rise of emissions of non-CO₂ greenhouses cases (Methane, Nitrous
oxide, CFCs).
Investigate techniques for geoengineering, including Solar Radiation Management.
All four of these must proceed simultaneously and in parallel. COP24 must make
this perfectly clear. There is utmost urgency and no time to “wait and see”.
Comment on this article
Hugh HuntReader in Engineering Dynamics and Vibration, University of
CambridgeHugh Hunt does not work for, consult, own shares in or receive funding
from any company or organisation that would benefit from this article, and has
disclosed no relevant affiliations beyond their academic appointment.
University of Cambridge provides funding as a member of The Conversation UK.--
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