Category Archives: Climate Change

Chart of the Day, 4 Feb 2015: Finding the Missing Heat and What It Means for Risk

The climate change debate generally focuses on the atmosphere–or rather two metres of the atmosphere through which we wander. Accordingly, the flagship statistic for climate change is the global mean temperature anomaly (latest update on this by me here). This is understandable: we are not fish.

Nonetheless, global warming refers to the globe, of which the atmosphere is a little piece. So we always have to remind ourselves of what warming goes where. From The Carbon Brief:

Where Is the Heat Going jpeg

Consequently, if the rate of transfer of heat into the ocean fluctuates (which it does), this will have a significant impact on atmospheric temperature. The largest short-term source of heat transfer volatility between atmosphere and ocean is the ENSO cycle, with El Ninos being associated with hot atmospheric years and La Ninas with cool ones.

Once we strip this factor out (plus the smaller impacts from the solar cycle and volcanic activity), then the upward march in atmospheric surface temperatures becomes a lot smoother. That is the difference between the orange and red lines in the chart below from a Real Climate blog post by Stefan Rahmstorf.

Temperature Anomaly without ENSO jpeg

Nonetheless, while we have had a broad-brush understanding of the atmosphere-ocean interface for quite some time, the granular detail on what energy is going where is only just emerging. The establishment of the ARGO network of temperature-measuring buoys is the game changer here (Carbon Brief; click for larger image).

ARGO jpeg

The data only goes back to 2006, but nevertheless this has been sufficient to give us a better picture of where the energy sinks exist. From a new paper in Nature Climate Change by Roemmich et al we see this (click for larger image):

Trends in Ocean Heat Content jpeg

Andrew Revkin also covers this story in his New York Times Dot Earth blog and relays an e-mail correspondence with climate scientist Yair Resenthal:

In an email chat, Yair Rosenthal of Rutgers University and Braddock Linsley of Columbia University, whose related work was explored here in 2013, said the Argo analysis appeared to support their view that giant subtropical gyres are the place where heat carried on currents from the tropics descends into the deeper ocean.

Linlsey said: “I think the Argo data point to the central gyre regions as key to the ocean-atmosphere heat exchange story.”

Rosenthal noted that this heat-banking process could buy humanity time, providing what he has called “a thermal buffer for global climate change,” particularly because the deeper ocean layers are still relatively cool (compared to much of the Holocene period since the end of the last ice age).

The critical point here from a risk perspective is that the heat-banking process “could” buy humanity time. The problem with this is that it also possibly “could not”.

We are at a stage where we are learning of the existence of the giant subtropical gyres but we know little about how they function or evolve through time. If these gyres have been responsible for an increase in heat transfer to the deep ocean over the last decade or so, it is quite possible that they could be responsible for a decrease in heat transfer at some future time. At this stage, we just don’t know.

We may have graduated from the stage when we were dealing with an ‘unknown unknown’ to a ‘known unknown’ but this hasn’t made much of an impact on how we can assess risk. In short, we are still learning about the probability distribution associated with warming outcomes. Yet within that distribution, a far-from-negligible chance of 4 degrees Celsius plus of temperature rise by end-century exists. Further, we know that a 4 degree rise would be catastrophic.

The good news is that the probability distribution of warming outcomes we are dealing with–unlike those for volcanoes or tsunamis–is one where we control one of the key variables: the trend in emissions. The bad news is that we aren’t controlling that variable.

Chart of the Day, 30 Jan 2015: Pick a Pathway (to Climate Nirvana or Climate Hell)

After yesterday’s post on China’s emissions, I will try to keep in a ‘cup half full’ frame of mind today.

The Intergovernmental Panel on Climate Change (IPCC) is an organisation for which I have great respect. But while their research may be applauded for its rigour,  communication with the wider world frequently lacks clarity (to put it mildly). Take, for example, the emissions scenarios, which in the Fifth Assessment Report (AR5) are called Representative Concentration Pathways (RCPs). Here are the RCPs and the change in temperature that accompanies them (Source: IPCC AR5, WG1).

Global Mean Temperature Change jpeg

I have spent many an hour grinding through IPCC reports trying to find clear explanations of what sits behind these pathways, but it is a painful process. Eventually, Skeptical Science saved the day by publishing “The Beginner’s Guide to Representative Concentration Pathways“.

There are four Representative Concentration Pathways: RCP 8.5, RPC 6, RCP 4.5 and RCP 2.6. The numbers refer to what is termed the ‘radiative forcing’, the change in net energy flow as measured in watts per square metre. Moreover, RCP 8.5 is expected to keep on increasing past 2100, RCP 6 and 4.5 will peak in 2100 and RCP 2.6 will have peaked prior to 21oo. Simplistically, a larger forcing means the globe will reach a higher mean temperature, as you can see in the chart above.

Surprisingly, AR5 is not particularly concerned with the socioeconomic assumptions that lie behind the RCPs. In this respect, the climate scientists behind the RCP concept are thinking the way economists often do: they are saying “imagine if we had condition X, what would be the output Y”. In this way, you can explore the model, and, hopefully, you obtain some insight which you can then take back to the real world.

I’m still a little uncomfortable with this. I think the IPCC should have chosen RCPs with highly transparent assumptions and realistic story lines. Instead, two of the four RCPs look utterly unrealistic to me. For example, to get to RCP 2.6 would require a transition away from fossil fuels that now looks impossible. And the good news? Well, RCP 8.5 looks barking mad to me too. Here are the emissions trajectories (from the Skeptical Science RCP report; click for larger image):

RCP Emission Trajectories jpeg

And if you concentrate on the blue line in the CO2 chart, you can see that around 24 giga tonnes of carbon are expected to be emitted in 2060. In yesterday’s blog post I was on working in units of tonnes of CO2. In the above chart, while the subject is CO2, the y-axis is in carbon. For those who have forgotten high school chemistry, you have to remember this:

CO2 jpeg

So when we move from calculations working in tonnes of carbon to tonnes of CO2 we have to multiple by 3.67 (44 ÷12) and vice versa. Joe Romm had a great piece in Climate Progress a while ago highlighting the number of people who get caught out through mixing up CO2 and carbon units. Accordingly, the 24 giga tonnes of carbon in 2060 is equivalent to about 88 giga tonnes of CO2. To put this in perspective, what are the big emitters putting out today:

Regional Emissions to 2019 jpeg

European emissions are already in decline and US emissions are flatlining. China’s emission growth will decelerate because its fixed-investment driven GDP growth model will come to the end of its natural life. China is also just about to enter its own demographic transition, and we have all see what such a transition did to Japanese economic growth (and by extension its emissions).

Obviously, India and other developing nations will increase their emissions, but they are unlikely to be able to replicate China’s export-led growth model. Further, with every passing year, the grid parity of renewables falls. Prime Minister Modi announced a push toward renewables when meeting President Obama. This was not just as a diplomatic gesture ahead of the Paris climate talks, but also as a pragmatic measure to buttress India’s energy independence and reduce the country’s exposure to volatile fossil fuel price movements.

So the cup half full is that RCP 8.5 looks unlikely–but the cup half empty is that RCP 6.5 is pretty awful climate-wise all the same.

Chart of the Day, 29 Jan 2015: China Slowdown a CO2 Emissions Silver Lining

If you follow the climate change debate over time, it is difficult not to get depressed: it’s the feeling of helplessness as the slow-motion cash crash takes place before your eyes.

So when a little bit of light shines through, it comes as a relief. And sometimes, hope comes from the most unlikely of sources–in this case China. It is almost a truism that as go China’s CO2 emissions, so go the world’s. See the chart below (Source: Trends in Global C02 Emissions Report; click for larger image):

Global CO2 Emissions jpeg

Very roughly, global CO2 emissions have gone from around 24 billion tonnes per annum in the early 1990s to around 36 billion tonnes today: an increase of 12 billion, or 50%.

Taking the top six emitters, we see can China’s prime role in this growth more clearly (click for larger image):

Top 6 Emitters jpeg

So we have seen China move from emitting around three billion tonnes of CO2 in the 1990s to around 10 billion tonnes today. Thus of the extra 12 billion tonnes of CO2 emitted per annum globally after 20 years, 7 billion has come from China.

The Global Carbon Project sees emissions continuing to grow to 43 billion tonnes in 2019 (note giga is equivalent to billion).

CO2 Emissions to 2019 jpeg

And again it is China leading the trend:

Regional Emissions to 2019 jpeg

And keep in mind that we have a CO2 budget of around 1,200 billion tonnes of CO2 before we commit the earth to 2 degrees Celsius of warming with a 66% probability. On current trends, that budget will be used up by about 2041, or in around 27 years.

Carbon Budget 2014 jpeg

Over that period, China is likely to emit approximately 15 billion tonnes of CO2 per year on average on present trends. That would mean that by 2041, China would have emitted about 400 billion tonnes of CO2, or a third of the total budget available. Next question: is there any way China can free up more of the budget?

A paper by Luukkanen et al provides us with a detailed decomposition of China’s future emissions using a Kaya identify with a sectoral overlay. To refresh your memory, the Kaya identity allows us to estimate future emissions based on population growth, GDP growth per person, energy intensity per unit of GDP, and carbon intensity per unit of energy (see my post “The Unbearable Logic of the Kaya Identity” for a little more detail).

The paper sets out three fuel-related emission scenarios: reference (business as usual), policy (following the government’s developmental plans) and industry (a  focus on heavy industry and investment-led growth).

China CO2 Scenarios jpeg

Note that the above charts are only looking at fuel combustion emissions. Accordingly, these numbers don’t tally with the Global Carbon Budget numbers that also add in agriculture and industry-related emissions. Nonetheless, where fuel emissions go, so will total emissions.

Here is where the silver lining comes: the most-muted emissions scenario above, termed ‘policy’, still looks far too high growth-oriented to me. Here are the assumptions that underpin this scenario `click for larger image):

China Sectoral Annual Growth Rates jpeg

In the policy scenario, a GDP growth rate of 7.4% is still forecast between 2016 and 2020, and then 5.2% growth  between 2021 and 2030. If you believe in a much quicker slow-down scenario, which I do, then these numbers look hopelessly optimistic (from a growth rather than climate perspective). See my post referring to Michael Pettis’ work.

If you then combine a much swifter descent to growth rates of 3-5%, plus a continued pivot from investment-led growth to consumption-led growth, and then add on an aggressive renewables roll out (which we are seeing), then China could free up an additional 100 billion tonnes of the carbon budget.

Frankly, that still doesn’t get us anywhere near capping climate change to 2 degrees of warming, but it gives us a little bit of extra time. And given where we are, every little bit helps.

Chart of the Day, 23 Jan 2015: Davos and the Incredible Melting Country

The rich and powerful are in Davos, Switzerland, for the annual gathering of the World Economic Forum from 21-24 January. While climate change is one topic up for discussion, I doubt the following image will pop up on many Powerpoint presentations (Source: Swiss Office of Meteorology, click for larger image):

Swiss Yearly Mean Temperature Anomaly jpeg

For the general public, the idea that the planet has warmed by 0.6 degrees Celsius since pre-industrial levels is hard to get too excited about. But Switzerland shows what happens when you translate 0.6 degrees into high elevations, at higher latitudes, and in areas distant from the sea. In short, we get warming many multiples higher than 0.6. And if you think 2014 was a one-off, it wasn’t: as usual with climate, its a bumpy, but consistent, upward path (source: here).

Swiss Average Mean Temperature Trend jpeg

Having spent a year in Switzerland, I know the people are of a stolid disposition. Yet I am surprised that they are not more agitated over the wholesale transformation of their country that is currently underway. Much of culture is born of climate and doubly so for the Swiss.

You can get a sense of what a different country Switzerland will become in the decades ahead by reading the Swiss Climate Impacts 2014 report, put together by leading Swiss government agencies, universities and research centres. For just a taste, here is the future for Switzerland’s snow and ice (note: we are currently progressing along the highest emissions scenario A2):

Switzerland Snow and Ice jpeg

I am stunned by how the people of any country, not just Switzerland, remain mute in the face of forces transforming a nation’s climate–and so culture–before their eyes.

Chart of the Day, 22 Jan 2015: Glaciers Going, Going, Gone

Last month, the World Glacier Monitoring Service (WGMS) came out with its bi-yearly mass balance estimate. Basically, this is a measure of the amount of melt. As expected, glaciers continue to lose mass:

Annual Mass Balance of Reference Glaciers jpeg

And on a cumulative basis:

Cumulative Mass Balance of Glaciers jepg

Although a little dated (2008), the WGMS also publishes an excellent report called “Global Glacier Changes: facts and figures“. And to get a better sense of what glacier retreat actually looks like check out James Balog’s Ted Talk on his glacier time lapse photo project (which later morphed into the Emmy Award winning documentary Chasing Ice):

Another excellent up-to-date source on glacier developments is the blog “From a Glacier’s Perspective” written by the leading glaciologist Mauri Pelto. Like most climate scientists, Pelto’s analysis is measured and considered; for example, he emphasises that not all glaciers are retreating since each glacier’s situation is unique. Moreover, some glaciers retreat and then find a new equilibrium.

But while this is true for individual glaciers (so providing fodder for climate skeptic web sites), it is not true in aggregate. From Pelto’s contribution to the alpine glacier section in the Bulletin of the American Meteorological Society’s annual State of the Climate publication:

The declining mass balance trend during a period of retreat indicates alpine glaciers are not approaching equilibrium and retreat will continue to be the dominant terminus response.

It is difficult not to get a little depressed over the fate of the planet when you see images of glacier disintegration such as these (Careser glacier in Italy, from the same BAMS report).

Careser Glacier jpeg

But don’t get depressed, get angry! Lobby your local politicians! Climate change consistently comes at the bottom of public concerns. It should be at the top.

Chart of the Day, 18 Jan 2015: An End to the Hiatus (Pause) in Temperature Rise?

Actually, two charts today taken from a presentation given by Gerald Meehl on the 5th January 2015 at the American Meteorological Society’s 95th annual conference. Meehl is a senior scientist at the National Center for Atmospheric Research (NCAR). First up, a chart showing that you should think of global warming as a stepwise movement as opposed to a smooth upward curve (click for larger image):

Hiatus Period jpeg

Where climate skeptics are wrong is to say that the last decade is not substantially  hotter than the previous decade. Where they are right is to say that over the course of the last decade, global surface temperatures have only warmed just a bit. But global warming doesn’t just incorporate the atmosphere, it includes the oceans as well. Global warming broadly defined to include the whole earth system has never stopped, it just shows up in different places at different times. From Meehl’s summary slide:

Global Warming Hasn't Stopped jpeg

The mechanism behind this shift is the Interdecadal Pacific Oscillation (IPO), which at times transports heat from the Pacific Ocean’s surface to the deep ocean.  Unfortunately, at other times, this process also works in reverse.

In the past, models, methodology and supercomputing power were not sufficient to capture the IPO and thus temperature hiatuses. However, Meehl believes that science has  progressed and we are now in a position to model and predict both temperature pauses and accelerations. And it looks like an acceleration is just about to begin (bottom left chart, click for larger image):

Hiatus Exit jpeg

Putting Climate Change Front and Centre

Climate change is often treated in political discourse as the topic that dare not speak its name. For me, the biggest shock of the last cycle of presidential debates was that Romney and Obama were never even asked for an opinion on what to do about global warming. The topic had become taboo. Too difficult and contentious to discuss in polite company.

In the UK, David Cameron is now completely mute on the subject, desperate as he is to stop the right of the conservative party haemorrhaging to UKIP. I think this is cowardly stance: if the Tory right are going to haemorrhage over Europe and immigration, I hardly feel that climate change will make much difference. In fact, sticking to the original Conservative Party commitment to run the “greenest government ever” would have significant appeal to the much-neglected centre.

So plaudits to Ed Milliband for raising climate change as a wedge issue in today’s issue of the newspaper The Independent on Sunday. The Daily Mail will claim that this will put yet more distance between Ed and that great, all powerful God of British politics: “White Van Man”. But I am not so sure. A true politician of stature should be able to shape fashion, not follow it. The commentary by Ed Milliband is here. See what you think.

The Green’s Grievance

Since returning to the UK three years ago, I have been astounded by the media coverage given to the United Kingdom Independence Party (UKIP). UKIP’s leadership, when pressed (a rare occurrence), convey a ramshackle and rather incoherent libertarian philosophy juxtaposed with 1950s-style little Englandism.

The Greens, meanwhile, get barely a mention, despite actually having a lot to say about the big topics of climate change, resource depletion, low growth and inequality. I don’t agree with much of the Green’s world view, but at least they get stuck into those issues which truly impact on our long-term welfare.

Leo Barasi at the Noise of the Crowd blog puts some numbers on this phenomenon. Monthly media mentions for the Greens are minimal despite their respectable polling numbers.

Green Media 1 jpeg

This is even more evident when we look at mentions per percentage point of votes:

Green Media 2 jpeg

In a perfect world, it would be wonderful if journalists spent time reading UKIP’s policies and asked some probing questions about them. UKIP’s barking mad energy policy, for example, rests on the assumption that CO2 emissions are benign and manmade climate change a hoax. Instead, we get another Nigel Farage pint-in-a-pub picture and 1,000 words on the “people’s army”.

I am told by media friends that the UKIP political narrative plays well  to the general public; conversely, the narrative of dangerous climate change doesn’t. But, ultimately, climate change is a narrative with no spectators—only participants.

Oxford Climate Forum 2014

I’m fresh from the Oxford Climate Forum, held this weekend. Presenters and panel speakers attempted to remain resolutely upbeat, but it was hard, at times, not to feel despondent—and that came through.

Professor Lord Giddens, the eminent British sociologist, and doyen of climate change politics, gave a presentation entitled “What Cause for hope?” Note, he gave the same speech a month previously at the LSE, available here (starting at 4 minutes). He commenced his speech with this statement:

Over the period from 2008 to 2014 today, on the one hand, the science of climate change, our understanding of climate change and our understanding of the dangers posed by climate change to the future of our civilisation has advanced substantially…………yet public opinion has become more indifferent.

Why should there be such a yawning gap between the dangers we face and our reactions to those dangers?

To answer this question, Giddens pointed to the fossil fuel lobby, the inability of a small coterie of scientists to convey the climate change message, the free-rider problem and, finally, the ongoing disputes between rich and poor countries over who should shoulder the burden of CO2 mitigation. Yet Giddens ultimately sees all these reasons as secondary; rather:

No other civilisation has ever intervened in nature remotely to the degree which we do on an everyday basis. Therefore, there is no historical situation, no historical record, no historical data from which we can draw upon to seek to mobilise public opinion against it…… The consequences of it are not there, they are to come.

I see the central difficultly of our world getting a stable future for itself in the 21st century around this situation; this situation being that we are likely to wait until there is some cataclysmic happening which can be unequivocally linked to climate change before we stir ourselves to action. But then, by definition, it will be too late, because we can’t get the greenhouse gases out of the atmosphere. I see this paradox as the central issue.

Giddens’ paradox also explains why, ironically, the young appear less concerned about climate change than the old, despite it being the young who will shoulder the burden in years to come. I’ve blogged about this issue here, but, in short, my explanation of the relative indifference of the young is that they have less experience of the fact that “shit happens”. Most fifty-year olds know of someone who has died of cancer, been killed in a road accident, attempted suicide, descended into alcoholism or ended up in prison. Must 18-year olds don’t.

Dr Adam Corner of Oxford’s Climate Outreach and Informational Network (COIN) didn’t quite see it this way. To COIN, climate change communication is a question of narrative. You can see their approach here. Moreover, a unifying feature of the forum was that narratives should be positive: climate change mitigation being an opportunity as much as an obligation. My take is that we have seen some pretty powerful political youth movements in the past that were a reaction to a threat, whether fascism, Vietnam or apartheid.

If there was some silver lining in Giddens speech, it was that a transformational technological change may arise. This is a similar line taken by the Google engineers Ross Kosingstein and David Fork in an article titled “What would it really take to reverse climate change“. They argue that we should be pouring money and resources into blue sky thinking, since it is only such thinking that could help prevent a catastrophe.

An unapologetic bare-knuckle prize fighter at the forum was Bob Ward from the Grantham Research Institute. Ward concentrated on calling out UKIP’s climate skeptic energy policy, a copy of which you can find here. It contains such gems as this:

We do not however regard CO2 as a pollutant. It is a natural trace gas in the atmosphere which is essential to plant growth and life on earth.

To which my riposte would be that water is vital to human life, but that does not mean to say we can’t drown in it.

Ward’s worry is that UKIP could quite easily perform the  role of king maker in any future minority Conservative Party government. As such, UKIP’s demand that the UK’s Climate Change Act should be torn up does no bode well for any constructive British participation in the Paris 2015 climate talks.

The media currently views climate change activism as essentially “boring”. In the 1930s, large parts of the British media viewed the rise of central European fascism as a matter of no consequence. How wrong they were, and how wrong they are now.

World on Brink of New Temperature Record (Despite a Coy El Niño)

Usually, a big, fat El Niño sets the world up for a new temperature record; see the correlation in the chart below. (For a good explanation of why, read this post by Bill Chameides of Duke University.)

TempAnomElNino jpeg

And for most of 2014, forecasters have been debating whether a big one would or wouldn’t show sometime soon. However, in its latest ENSO forecast, out 6th November, the US government’s National Oceanic and Atmospheric Administration (NOAA) has grown far more “iffy”:

The CPC/IRI ENSO forecast has dropped the likelihood of El Niño again, to 58%, despite the presence of “borderline” El Niño conditions (i.e. warmer equatorial Pacific sea surface temperature, and some reduction in rain over Indonesia). El Niño is still expected, but with less confidence.

But the Australians, in an even more recent update (18th November), think we may see a last minute appearance for this year’s elusive El Niño:

The Pacific Ocean has shown some renewed signs of El Niño development in recent weeks. Above-average temperatures in the tropical Pacific Ocean have warmed further in the past fortnight, while the Southern Oscillation Index (SOI) has generally been in excess of El Niño thresholds for the past three months. Climate models suggest current conditions will either persist or strengthen. These factors mean the Bureau’s ENSO Tracker Status has been upgraded from WATCH to ALERT level, indicating at least a 70% chance of El Niño occurring.

Regardless of whether El Niño shows, it is too late in the year for it to significantly pump up global temperature anomalies. So it should be tough for 2014 to take the number one spot. Or will it?

From Columbia University’s Earth Institute, we can see where the records stand:

Top 10 Warm Years jpeg

Note: the slight differences between the anomalies recorded by the two US government agencies, NOAA and NASA, are due to different measurement procedures. Nonetheless, for both time series, the years from the last decade dominate the table and broadly align. And for 2014?

The NASA data (here) have been published out to October and show an average temperature anomaly for the first 10 months of the year of 0.66 ⁰C. The nine months of data put out so far by NOAA (here) average 0.67 ⁰C. While the Pacific Ocean may not be characterised as exhibiting a full-blown El Niño, it certainly is on the warm side, with the result that the final months of the year are likely to come in well above average, temperature-wise.

So the annual global mean temperature record looks almost in the bag for 2014. Whether this record will be enough to put paid to the climate skeptic meme that global warming stopped in 1998 is doubtful (the old records will likely be beaten but not smashed). But the evolving data do show that when the next El Niño arrives, it will build on an ever hotter base.

Thus mankind presses ever further into unchartered temperature territory. The foolhardiness of this risk-taking amazes me.