Disclaimer: I am now retired, and am therefore no longer
an expert on anything. This blog post
presents only my opinions, and anything in it should not be relied on.
As I have argued before, human metrics on how well we are
coping with climate change can be highly misleading, usually on the side of
false optimism. Two metrics that are
clearly not thus biased are:
1.
Measurements of atmospheric CO2 at Mauna Loa in
Hawaii, which have been recorded since 1959;
2.
Estimates of Arctic sea ice volume (with extent
serving as a loose approximation), especially at minimum in September, which
have been carried out since the 1980s.
Over the past few years, I have covered the drumbeat of bad
news from those two metrics, indicating that we are in a “business as usual”
scenario that is accelerating climate change.
In the first half of 2018, what has happened in both cases is that the
metrics are not following a “worst possible case” path – hence the “relatively
good” part of the title. At the same
time, there is no clearly apparent indication that we are deviating from our “business
as usual” scenario – mitigation is not clearly having any effect. It is possible, however, that we are seeing
the beginnings of an effect; it’s just not possible to detect it in the
statistical “noise.” And given that
scientists are now talking about a “tipping point” in the near future in which
not only a frightening 2 degrees C temperature by 2100 is locked in, but also
follow-on feedbacks (like permafrost melt) that take temperature rise
eventually to a far more disastrous 3-4 degrees C – well, that’s the
underlying, ongoing bad news.
Of course, this summer’s everlasting heat waves in the US,
Europe, and the Middle East – heat waves clearly caused primarily by human-generated
CO2 emissions and the resulting climate change – make the “new abnormal”
obvious to those of us who are not wilfully blind. But for anyone following the subject with an
open mind, the heat waves are not a surprise.
So let’s take a look at each metric.
The El Nino Effect Recedes
From late 2016 to around June of 2017, the El Nino effect
crested, and, as it has done in the past (e.g., 1998) drove both temperatures
and the rate of CO2 rise skyward. Where
2013-2015 saw an unprecedented streak of 3 years of greater than 2 ppm atmospheric
CO2 growth, 2016 and 2017 both saw record-breaking growth of around 3 ppm
(hiding a brief spurt to almost 4 ppm). 1998
(2.86 ppm) was followed by a year or two of growth around 1 ppm – in fact,
slower than 1996-7. But the percentage
rate of rise has also been rising over the years (it reached almost 1% in early
2017, 4 ppm over 404 ppm). Therefore, it
seemed a real possibility that 2018 would see 2.5 ppm growth. Indeed, we saw 2.5 ppm growth as late as the
first month or two of 2018.
Now, however, weekly and monthly growth has settled back to
a 1.5-2 ppm rate, consistently since early 1998. Even a 2 ppm rate gives hope that El Nino did
not mean a permanent uptick in the rate of rise. A 1.5 ppm rate would seem to indicate that
2018 is following the 1999 script – a dip in the rate of rise, possibly because
of the follow-on La Nina. It might even
indicate a slight – very slight – decrease in the underlying rate of rise
(i.e., the rate of rise with no El Nino or La Nina going on). And that, as I noted above, is the first indication
I have seen that things might possibly be diverging from “business as usual”.
Of course, there’s always the background of bad news. In this case, it lies in the fact that
whereas ever since I started following CO Mauna Loa 6 or 7 years ago CO2 levels
in year 201x were about 10 ppm greater than in year 200x (10 years before), right
now CO2 levels are about 13.5 ppm greater than in year 2008. So, even if the El Nino effect has ended, the
underlying amount of rise may still be increasing.
The best indicator that our efforts are making a difference
would be two years of 1 ppm rise or less (CO2 Mauna Loa measures the yearly amount
of rise by averaging the Nov.-Feb. monthly rises). Alas, no such trend has shown up in the data
yet.
Arctic Sea Ice: Not In Stasis, Not in Free Fall
Over the last 2 years, the “new normal” in Arctic sea ice
advance and retreat has become apparent.
It involves both unprecedented heat in winter, leading to new low extent
maxima, and a cloudy and stormy July and August (key melt months), apparently negating
the effects of the winter melt. However,
volume continues to follow a downward overall trend (if far more linear and
closer to flat-line than the apparently exponential “free fall” until 2012,
which had some predicting “ice-free in 2018”).
As Neven’s Arctic Sea Ice blog (neven1.typepad.com) continues
to show, however, “ice-free in September” still appears only a matter of time (at
a best guess, according to some statisticians, in the early 2030s). Subsea temperatures (SSTs) in key parts of
the Arctic like above Norway and in the Bering Sea continue to rise and impact
sea ice formation in those areas. As the
ice inherited from winter thins, we are beginning to see storms that actually
break up the weaker ice into pieces, encouraging increased export of ice to the
south via the Fram Strait. The ice is so
thin that a few days ago an icebreaker carrying scientists had to go effectively
all the way to the North Pole to find ice thick enough to support their
instruments for any length of time.
So the relatively good news is that it appears highly
unlikely that this year will see a new low extent, much less an ice-free
moment. The underlying, ongoing bad news
is that eventually the rise in SSTs will inevitably overcome the counteracting
cloudiness in July and August (and that assumes that the cloudiness will
persist). Since 1980, extent at maximum
has shrunk perhaps 12%, while extent at minimum has shrunk perhaps 45% (volume
shows sharper decreases). And in this,
unlike CO2 Mauna Loa, there is no trace of a hint that the process is slowing
down or reversing due to CO2 emissions reductions. Nor would we expect there to be such an
indication, given that we have only gotten globally serious about emissions
reduction in the last 3 years (yes, I recognize that Europe is an exception).
The Challenge
The question the above analysis raises is: What will it take to really make a
significant impact on our carbon emissions – much less the dramatic reductions scientists
have been calling for? I see no precise answer
at the moment. What I do know is that
what we are doing needs to be done even faster, far more extensively – because the
last few years have also seen a great increase in understanding on the details
of change, as I have tried to show in some of my Reading New Thoughts
posts. The ways are increasingly there;
the will is not. And that, I think,
along with countering the disgustingly murderous role of President Trump in
particular in climate change (I am thinking of Hurricane Maria and Puerto Rico as
an obvious example), should be the main task of the rest of 2018.
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