RCP Possible Emissions Path
Good Morning, Vietnam…
Ivo Welch
December 31, 2021
…the weather out there today is hot and shitty with continued hot and shitty in the afternoon. Tomorrow a chance of continued crappy with a pissy weather front coming down from the north. Basically, it’s hotter than a snake’s ass in a wagon rut. — Adrian Cronauer.
GHG concentration has been growing:
“stock” in the atmosphere is 410 ppm now (base = 280 ppm),
this is about 50% higher (doubling => about 3°C)
current growth rate is 2.5 ppm/year.
2.5ppm is not so bad—until you think in terms of generations
emissions are accelerating
but effects are more linearly increasing
will continue growing for at least 30 more years
global temperature has been increasing
not yet in equilibrium
most relevant data: last 30-200 years
increase attributable greatly or exclusively to GHG emissions
the already-emitted gases suggest an “equilibrium” temperature increase of 1.5°C
due to 50% GHG increase
only 0.7-1°C has occurred to-date, the other half is still on its way,
due to heat reservoirs and/or delaying SO2 reflectivity from coal.
intergovernmental panel on climate change.
these are not the fossil-fuel folks, but the climate scientists that worry about warming.
they are our main information source.
data almost always objective, but
occasionally (possibly) biased assessments.
RCP: representative concentration pathway,
named based on increases in watts/m2,
mostly about expected outcomes, but cognizant
their RCPs are their expertise. their SCPs are more dubious.
benchmarks:
1,360 W/m2 on top of atmosphere (avg).
1,000 W/m2 on ground (avg).
climate change will likely be severe
RCP 4.0 (extra 4 W/m2) — 2.5°C.
think from today, another +1.5°C.
active “tough-sacrifice” intervention.
RCP 6.0 (extra 6 W/m2) — 3.0°C.
think from today, another +2.0°C.
very “mild” intervention.
most likely Earth’s current pathway
opinion: only smart intervention can bend RCP lower
trains that have left station:
RCP 2.5 — forget it
RCP 8.0 — forget it
watch it—many sites still publish alarmist assessments under RCP 8.0.
COP (UN conference of the [197] parties)
RCP 4 vs. RCP 6.
not much chance that COP treaty could do
better than RCP 4, or
worse than RCP 6.
…whether you like it or not.
💊
realistic emission peaks: ≈ 2050.
latest suggest 0.3 by 2100, i.e., lower range.
affirmatively not on expected RCP path
what will a temperature shift of 2-3°C mean?
boston → nyc → washington → raleigh.
los angeles → las vegas or austin.
can usa survive this kind of shift?
can civilization survive it?
can the world survive it?
affirmatively not on much worse RCP path, either
climate change will become much more noticeable than it is today.
the IPCC tells us that this temperature change has become inevitable.
we have just (20 years) been beginning to truly feel warming
especially in northern latitudes and at night
don’t know why exactly
climate-change vs no-climate-change is not the relevant decision margin!
what is the correct decision margin?
| delta | ||
|---|---|---|
| decrease | 1500-1800 | -0.4°C |
| increase | 1800-2020 | +1.5°C |
| do-nada rcp6 further increase | 2020-2100 | +2.1°C |
| activist rcp4 further increase | 2020-2100 | +1.7°C |
| GHG net curtailment | activist | -0.4°C |
do not confuse expected warming with reduced expected warming if humanity fights climate change.
fighting climate change is all about a reduction of 0.3-0.5°C.
it is never about a larger reduction of 2-3°C.
if 2-3°C were to (unexpectedly) cause more harm (such as mass extinctions), it would likely still remain so even if COP “won,” albeit maybe with a little lower probability.
mass extinctions are primarily due to habitat loss and human population growth and not due to temperature changes per se.
I am in favor of intervention, but not in the way that activists are proposing.
I did not design the world or the choices before us. don’t blame me. 💊
not Climate-Change effects
what will an extra mean temperature increase of 0.3-0.5°C really mean?
it will be big, noticeable, and meaningful,
but will it be relatively Earth shattering? no.
examples of 0.3-0.5°C differences:
calgary ↔︎ st. johns ↔︎ st.pierre.
toronto ↔︎ chicago/detroit ↔︎ denver ↔︎ pittsburgh ↔︎ boise ↔︎ columbus.
san diego/tijuana ↔︎ los angeles.
las vegas ↔︎ san antonio.
temperature can increase lots more in some locations
temperature could increase a lot more than expected
but also a lot less
we will discuss risks below again
on average, risks justify more caution
this also depends on how quickly humanity could react.
if undoing response could take < 5 years, should we see first?
we don’t treat cancer ahead of time.
we want to measure economic damages.
most of Earth will change
not every place will get worse!
but most places will just be a little different.
the important problems will be today’s ‘marginal’ zones:
not the sahara, but the sahel (85 mln people).
warming brings more water vapor and possibly rain, too.
so far, temperature has increased most in extreme and polar latitudes, especially Northern latitudes.
boffins are not sure why.
could change.
most warming damage is forecast to occur in agriculture.
huh?
if reduced food production is the main worldwide problem, it would be cheap to fix:
agro deficits would be easy to cover
agro productivity could even increase with more CO2, adaptation, and new GMO draught-resistant crops
most increasing deaths are forecast to come from preventable and curable diseases, especially malaria.
huh?
if increased malaria is the main worldwide problem, it would be cheap and easy to fix:
we could even wipe out specific mosquito species altogether
how long should we wait?
fortunately, my own kids are not dying from it.
let’s place the ethical review boards’ kids into these regions, too.
slow decisions feel like very elitist luxury ethics to me.
diarrhoea
heat stress
what if people move? over 50 years?
what about cold deaths?
if food and disease are really the main problems, “we” could cure them very cheaply.
in this were the case, it would be cheaper to cure the symptoms than the disease.
indeed, probably 2-3 orders of magnitude cheaper.
destruction is both climate and non-climate related.
habitat destruction is much harder to fix than climate change,
it is also way beyond our course’s scope,
and there are no obvious solutions.
but “the environment” is a ‘luxury good’.
richer people demand healthier environments
a healthy ecology is valued higher in the OECD than it is in brazil, india, sudan, or nigeria.
bangladesh’s problem today is abject poverty, not global warming in 50-100 years.
precipitation Increases in many places,
but hard to predict where:
the sahara dried up a few thousand years ago
maybe from goats overgrazing
sand feeds cloud formation / rain ; has high albedo
but warming → more water vapor → more precipitation.
some will be torrential and useless,
but most should be productive and useful,
just as it is today.
more extreme events!? bad.
more CO2 and rain!? good?
bangladesh, indonesia, florida, netherlands.
but not afghanistan and iowa.
the activist approach focuses primarily or only on the cost of climate change.
it often completely ignores:
the benefits of climate change
the cost of fighting climate change
this is the “Greenpeace problem.”
the economic approach weighs costs against benefits:
how much would it cost to reduce climate change?
how fast and effective would harm be reduced?
should we do it now or see what happens first?
how many more people will die because they could not escape poverty as quickly?
how do we count improvements in other areas?
is there an optimal Earth temperature??
damage will be limited because of adaptation
not just humans but other species, too
polar bears are almost a sub-species of grizzly bears
color, swimming, and feet/claw differences
scientists’ damage estimates in 100 years are speculative
19th century: 70% of americans moved from the land to cities.
moving has become much cheaper in 21st century
many winners and losers.
many transition hardships:
millions will suffer, billions may be harmed,
but billions or millions may also gain.
rich people (“you”) will basically be fine.
poor people may not be able to escape or to adjust.
is climate activism about/for the poor?
cross-subsidize from winners to losers?
oecd could help bangladesh and sahel:
could be cheaper to help the poor than to limit emissions;
could be cheaper to move sahelis than saving the sahel!
moving sahelis would be expensive, of course — but so is curbing CO2.
otoh, sahel may turn green again?!
is climate activism about/for the poor?
take a cold hard look at the evidence.
when their pocketbooks are at stake:
the rich do not care much about poor,
neither rich countries about poor countries,
nor rich people about the poor in their own countries.
if they did, the world would be different.
ps: plus, there’d be other problems:
aid may not be effective (see easterly)?
aid may not be appreciated: local tribalism, anti-colonialism, and cultural resistance.
aid may require force. who wants to take on congolese warlords?
still, a lot of undone good is possible (un wfp, unicef),
but the rich really don’t much care. 💊
is climate activism about saving the poor (or ‘communities of color’)?
does activism offer realistic approaches?
or just idealistic blabber of rich youth?
… when their own pocketbooks are not at stake.
… and when they are afraid of their own hides?
collective shame of humanity, read peter singer.
… whether you like it or not. 💊
think not 2.5°C, but 2.0-3.5°C.
think not 3.0°C, but 2.5-4.0°C.
any expected uncertainty adds to the problem:
risk → requires more not less concern,
e.g., think upper end of spectrum,
but don’t plan based on worst-case only.
responsiveness and adaptation will counter variation and uncertainty.
nice but dated web page of cc effects
fairly typical cc assessments:
probably all true.
yet focuses only on negatives,
ignores any positives whatsoever — really?
often easies to predict negatives, not positives.
equivalent for econ growth and creative (job) destruction.
what is optimal Earth temperature?
if we are indeed already hugely above optimal Earth temp for humans and the ecology, then boffins could likely reduce global temperature very cheaply, with modest negative side effects. it would make sense if cooling benefits would be huge.
I don’t think the world is there (yet?)…
send me (quantitative) evidence, please.
I have been looking for more exp. harm.
it’s not in hurricanes, floods, etc.
please no vacuous statements:
“one life lost is too many.”
“no child left behind.”
such statements are context-specific, of course.
can make sense for doc in emergency room, but not in traffic planning.
yes, people die. yes, death is terrible.
in fact, about 50 (soon 100) million people die per year.
negligibly few die from climate change.
10,000 deaths are just 0.000,125%.
so few deaths matter little in the global balance—of course, except when they affect people you know.
boffins must analyze ugly tradeoffs.
💊
less time for species to adapt.
yet many species will move habitat,
except for polar bears?!
cc can amplify habitat destruction.
‘seafood’ may be worst of many sins.
extinction is not primarily cc.
rapid cc is not truly unprecedented.
think asteroid impacts.
think “real” supervolcanoes.
permafrost (methane).
albedo (i.e., reflectivity).
clouds?! (high vs. low?)
larger fires.
planet-wide fires maintain appropriate oxygen levels for life.
range: 16% - 23%. today: 21%.
what do we not know?
where does the next sahara feedback loop lie?
change can bring the unexpected:
could be bad.
could be real bad.
could be real, real bad.
we do not live primarily planning for World War 3.
well, actually, some crazy people do.
and some folks in hollywood think about it.
worst-case scenario could be very bad,
but it may not hit us for hundreds of years
…or even ever.
keep appropriate perspective:
in human history, 21st century is the best time ever to live in, by far,
especially where we (you students and I) are (OECD),
even for bottom 10%, 20%, or 50%.
human-made (or not) is unimportant:
mass extinctions were natural, too.
at least 5 great extinctions.
dinosaurs were not the worst, by far.
250 mln years ago, 96% of marine and 70% of land species died.
our cave clans survived worlds 6-8°C colder,
with highly unstable climates,
and much less technology.
…seems way worse to me!
civilization has never lived in a 3°C warmer world,
great changes will happen sooner or later,
will civilization survive global warming?
of course, yes!
will the human species survive global warming?
of course, yes!
will you survive?
of course, not. life is a terminal disease.
will “the planet” survive global warming? are you kidding? we humans are a minor infestation of the planet.
apophis 99942 will fly below our satellites on April 13, 2029 21:46 UTC
bright side: if it had hit, global warming would no longer have been a problem.
supervolcanos (e.g., yellowstone)
global crop failures for 5-10 years anyone?
expect 1 / 500,000 years, or just 50,000?
doomsday seems not imminent,
much less from climate change:
serious concern remains warranted.
the expected temperature increase is big;
the planet will change quite a lot
but
the adapted net effects will remain small
worse human misery already exists today
worse environmental crises already exist today
belt intervention will only have a small effect;
“humanity” (who?) should be prepared for:
global warming foremost,
but also secondarily for global cooling.