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by David Spratt

Third in a series

Danger from implied temperature increase

The current level of atmospheric CO2 only is sufficient to increase the global temperature at equilibrium by +1.5°C, based on the standard assumption of near-term climate sensitivity of 3°C for doubled CO2.

If all current greenhouse gases are taken into account, then:

The observed increase in the concentration of greenhouse gases (GHGs) since the pre-industrial era has most likely committed the world to a warming of 2.4°C (within a range of +1.4°C to +4.3°C) above the pre-industrial surface temperatures. (Ramanthan and Feng)

And the 2007 IPCC Synthesis report (Table 5.1 on emission scenarios) also shows that for levels of greenhouse gases that have already been achieved (CO2 in the range of 350–400 ppm, CO2e in the range 445–490 ppm) and peaking by 2015, the likely temperature rise is in the range of 2–2.4°C.

These scenarios include short-lived gases such as methane, which degrades out of the atmosphere in a decade, and also nitrous oxide, which has an atmospheric lifetime of around a century. On the other hand, the fact that temperatures are not already much higher than they are today is due principally to the large-scale emission of very short-lived (10 days) aerosols such as soot and exhausts from burning fossil fuels, industrial pollution and dust storms, which are providing temporary cooling. The effect is known popularly as “global dimming”, because the overall aerosol impact is to reduce, or dim, the sun’s radiation, thus masking some of the heating effect of greenhouse gases. The aerosol impact is not precisely known, but Ramanthan and Feng estimate it as high as ~1°C. As the world moves to low-emission technologies, most of the aerosols and their temporary cooling will be lost. Recent research finds that quickly eliminating all greenhouse gas emissions (and necessarily the associated aerosols) would produce warming of between 0.25 and 0.5 °C over the decade immediately following (Matthews and Zickfield; Hansen, Sato et al.).

A practical consideration of “dangerous” can include the question as to whether there are tipping points or “concerns” activated for the elevated temperatures that we are generally considered to be already committed to: conservatively in the range say +1.5 to 2°C and, more pragmatically, in the range of 2 to 2.4°C if all current greenhouse gases are considered. A related question is whether the +1.5°C goal advocated by the small island states and surveyed recently by Climate Action Network Europe and Climate Analytics would avoid “dangerous” climate change and significant tipping points.

This is a broad topic, but four recent important research findings on impacts for the current committed warming are arresting:

Greenland Ice Sheet tipping point

The tipping point for GIS has been revised down by Robinson, Calov et al. to +1.6ºC (uncertainty range of +0.8-+3.2ºC) above pre-industrial, just as regional temperatures are increasing at three-to-four times faster than the global average, and the increased heat trapped in the Arctic due to the loss of reflective sea ice ensures an acceleration in the Greenland melt rate.  If the lower Greenland boundary in the uncertainty range turned out to be right, then with current warming of +0.8ºC over pre-industrial we have already reached Greenland’s tipping point.  And, with temperature rises in the pipeline, the upward trajectory of annual greenhouse gas emissions, the projected future increases in fossil fuel use, and the continuing political impasse in international climate negotiations, we are very likely to hit the best estimate of +1.6ºC within a decade or two at most.

Coral reefs

Frieler, Meinshausen et al. show that “preserving more than 10 per cent of coral reefs worldwide would require limiting warming to below +1.5°C (atmosphere–ocean general circulation models (AOGCMs) range: 1.3–1.8°C) relative to pre-industrial levels”.  Obviously at less than 10 per cent, the reefs would be remnant, and reef systems as we know them today would be a historical footnote.  Already, the data suggests that the global area of reef systems has already been reduced by half. A sober discussion of coral reef prospects can be found in Roger Bradbury’s “A World Without Coral Reefs”  and Gary Pearce’s “Zombie reefs as a harbinger for catastrophic future”.  The opening of Bradbury’s article is to the point:

It’s past time to tell the truth about the state of the world’s coral reefs, the nurseries of tropical coastal fish stocks.  They have become zombie ecosystems, neither dead nor truly alive in any functional sense, and on a trajectory to collapse within a human generation.  There will be remnants here and there, but the global coral reef ecosystem — with its storehouse of biodiversity and fisheries supporting millions of the world’s poor — will cease to be.

3c. Arctic carbon stores

As Climate Progress recently noted: “We’ve known for a while that ‘permafrost’ was a misnomer” because thawing permafrost feedback will turn the Arctic from a net carbon sink to a net source in the 2020s and defrosting permafrost will likely add up to 1ºC to total global warming by 2100.   A 2012 UNEP report on Policy implications of warming permafrost says the recent observations “indicate that large-scale thawing of permafrost may have already started.”  In February 2013, scientists using radiometric dating techniques on Russian cave formations to measure historic melting rates warned that a +1.5ºC global rise in temperature compared to pre-industrial was enough to start a general permafrost melt.  Vaks, Gutareva et al. found that “global climates only slightly warmer than today are sufficient to thaw extensive regions of permafrost.” Vaks says that: “1.5ºC appears to be something of a tipping point”.

Previously a study of East Siberian permafrost by Khvorostyanov, Ciais et al.  found that once mobilised, the process would be self-maintaining due to “deep respiration and methanogenesis” (formation of methane by microbes).  In other words, the microbial action that produces methane as the carbon stores melt would produce sufficient heat to maintain the process: “once active layer deepening in response to atmospheric warming is enough to trigger deep-soil respiration, and soil microorganisms are activated to produce enough heat, the mobilization of soil carbon can be very strong and self-sustainable”.

A sharp scientific debate has started on the stability of large methane clathrate stores just below the ocean floor on the shallow East Siberian Sea, following the publication in July 2013 of research by Whiteman, Hope and Wadhams which said that the release of a single giant “pulse” of methane from thawing Arctic permafrost beneath the East Siberian sea could come with a $60 trillion global price tag. Wadhams says “the loss of sea ice leads to seabed warming, which leads to offshore permafrost melt , which leads to methane release, which leads to enhanced warming, which leads to even more rapid uncovering of seabed”, and this is not “a low probability event”.

Multiple targets reduce allowable warming

Steinacher, Joos et al. explore the interaction of targets in emissions reductions, focussing on the 2ºC temperature goal. They find that when multiple climate targets are set (such as food production capacity, ocean acidity, atmospheric temperature), “allowable cumulative emissions are greatly reduced from those inferred from the temperature target alone”. In fact, “When we consider all targets jointly, CO2 emissions have to be cut twice as much as if we only want to meet the 2ºC target.”

Lessons from climate history

Another fruitful line of inquiry on whether climate change is already “dangerous” is to look at the paleo-climate (climate history) record for circumstances analogous to present conditions to learn what planetary and climate conditions were like at that time.  With current CO2 levels at 400 ppm, a useful comparison is the Pliocene (3–5 million years ago).  The research body is large and growing in this area, but here are some examples:

Sea-levels

Rohling, Grant et al.  find that during the mid-Pliocene, when greenhouse gases were similar to today, sea levels were more than 20 metres higher than today “we estimate sea level for the Middle Pliocene epoch (3.0–3.5 Myr ago) – a period with near-modern CO2 levels – at 25±5 metres above present, which is validated by independent sea-level data”. Likewise Hansen, Sato et al. find that “during the middle-Pliocene… we find sea level fluctuations of 20-40 metres associated with global temperature variations between today’s temperature and +3°C”.

Speed of sea-level rise

The speed of sea-level rise may far exceed the current, rather reticent estimates that are used for policy purposes.  Blancon, Eisenhauer et al. examined the paleo-climate record and showed a sea-level rises of 3 metres in 50 years due to the rapid melting of ice sheets 123,000 years ago in the Eemian, when the energy imbalance in the climate system was less than at present.

Polar feedbacks

Hansen, Sato et al. find that current temperatures are at least as high as the Holocene Maximum (i.e., as high as they have been over the last 10,000 years).  They sum up:

Earth at peak Holocene temperature is poised such that additional warming instigates large amplifying high-latitude feedbacks.  Mechanisms on the verge of being instigated include loss of Arctic sea ice, shrinkage of the Greenland ice sheet, loss of Antarctic ice shelves, and shrinkage of the Antarctic ice sheets.  These are not runaway feedbacks, but together they strongly amplify the impacts in polar regions of a positive (warming) climate forcing…  Augmentation of peak Holocene temperature by even +1ºC would be sufficient to trigger powerful amplifying polar feedbacks, leading to a planet at least as warm as in the Eemian and Holsteinian periods, making ice sheet disintegration and large sea level rise inevitable.

[It is relevant here to note that warming in the pipeline due to thermal inertia, plus warming associated with the loss of aerosols, is greater than +1ºC.]

And during the Pliocene, with atmospheric greenhouse levels similar to today, the northern hemisphere was free of glaciers and ice sheets and beech trees grew in the Transantarctic Mountains. There are also strong indications that permanent El Nino conditions prevailed.

4d. Arctic carbon stores

As discussed above, scientists using radiometric dating techniques on Russian cave formations to measure historic melting rates going back 500,000 years conclude that a +1.5ºC global rise in temperature compared to pre-industrial is enough to initiate widespread permafrost melt.

In May this year, Brigham-Grette, Melles et al. published evidence from Lake El’gygytgyn, in north-east Arctic Russia, showing that 3.6–3.4 million years ago, summer mid-Pliocene temperatures locally were ~8°C warmer than today, when CO2 was ~400 ppm.  This is highly significant because researchers including Celia Bitz and Philippe Ciais have previously found that the tipping point for the large-scale loss of permafrost carbon is around +8ºC  to 10ºC regional temperature increase.  Caias told the March 2009 Copenhagen climate science conference that: “A global average increase in air temperatures of +2ºC and a few unusually hot years could see permafrost soil temperatures reach the +8ºC threshold for releasing billions of tonnes of carbon dioxide and methane”. So, if the current level of greenhouse gases is enough to produce Arctic regional warming of ~+8°C and that is a likely tipping point for large-scale permafrost loss, we have reached a disturbing milestone.

Even more disturbing is new research from Ballantyne, Axford et al. which says that during the Pliocene epoch, when CO2 levels were ~400 ppm, Arctic surface temperatures were 15-20°C warmer than today’s surface temperatures. They suggest that much of the surface warming likely was due to ice-free conditions in the Arctic. Compared to the estimated tipping point for the large-scale loss of permafrost carbon of +8º– 10ºC regional warming, this research confirms both that the current level of greenhouse gases is sufficient to both create a sea-ice free Arctic, and Arctic warming more than sufficient to trigger large-scale loss of permafrost carbon.

Next post: Climate safety and the emissions reduction challenge

A look at global population trends

Too many people is a big problem, but too few is a concern as well.

By Dan Murphy, Staff writer / September 21, 2013

The story of the 21st century has been one of falling birthrates, rising standards of living, and a revolution in food production. But the global picture is uneven: As populations decline in wealthier nations, in other countries – particularly in Africa, says a new report – they are rising at rates that may mire their people in poverty.

Q: What countries are growing the fastest?

The 10 countries with the highest fertility rates are all in Africa, led by Niger, where women give birth to an average of 7.6 children. Burkina Faso, with a fertility rate of 6 children per woman, is the slowest growing of the 10, all of which are among the world’s poorest countries as well. Recent research by the Population Reference Bureau in Washington projects that Africa’s population will more than double by 2050, from 1.1 billion people today to 2.4 billion. Nigeria, already the most populous nation on the continent with 174 million people, is projected to be the third most populous in the world by 2050, with 440 million, after China and India.

Q: What countries are growing the slowest?

The surprising leader is Bosnia-Herzegovina, with just 1.2 children per woman. The others in the top 10 least-fertile countries all average 1.3 children per woman and include three Asian countries: Taiwan, Singapore, and South Korea. The others are in Europe: Moldova, Poland, Portugal, Spain, Slovakia, and Hungary. The fertility rate in the United States is 1.9 children per woman, which implies a declining population. But America is expected to grow in the coming decades because of immigration.

The average global fertility rate is now 2.5 children per woman, down from almost 5 in 1960.

Q: So does that mean Africa is in trouble and everyone else is not?

Not necessarily. While there are major concerns that population growth will outstrip economic growth in many African countries, many other countries are deeply worried about the possibility of declining populations, which undercut economic growth and leave fewer and fewer workers to provide for systems that will burgeon with retirees.

Even China is worried about the effect of a declining population 35 years after instituting its draconian “one child” policy. China was concerned that it wouldn’t be able to feed its people when it made it illegal for couples to have more than one child and engaged in forced sterilizations and abortions to cut population growth. China’s population, now at 1.35 billion, is expected to drop by 2050.

Q: What are the solutions?

There aren’t any easy ones when it comes to the African countries whose population growth rates are so high. Rising income and education levels lead to lower fertility rates, but accomplishing those first two things is challenging – even more so when a poor country’s limited educational resources are swamped by a vast number of children.

Consider Niger, which the Population Reference Bureau compares to the Netherlands, since both countries have roughly 17 million people today. At the moment, 50 percent of Niger’s population is younger than age 15, compared with 17 percent of the Netherlands’. And given Niger’s extremely low standard of living, parents in Niger have an unfortunate incentive to bear more children: The bureau estimates that 43,000 infants died in Niger last year. In the Netherlands, by contrast, the figure was 650.

Q: Which countries are expected to have the largest populations in 2050?

India, which has 1.3 billion people today, is expected to supplant China in the top spot by then with a projected population of 1.65 billion. The US, though still growing, will fall from its current No. 3 position, with 316 million, even though it will rise to a projected 400 million. That will put it at No. 4, behind Nigeria, which is about one-tenth the size of the US in area.

Ethiopia and Congo are expected to join the top 10 by 2050, pushing out Japan and Russia. Congo‘s population is projected to rise from 71 million today to 182 million, and Ethiopia’s from 89 million now to 178 million.

Op-Ed Columnist

Mother Nature and the Middle Class

By THOMAS L. FRIEDMAN

Published: September 21, 2013 2 Comments

Josh Haner/The New York Times

Thomas L. Friedman

Go to Columnist Page »

So go back to sleep? Not so fast. I can guarantee that the next 30 years will not be the same old, same old. Two huge new forces have muscled their way into the center of both Egyptian and Iranian politics, and they will bust open their old tired duopolies.

The first newcomer is Mother Nature. Do not mess with Mother Nature. Iran’s population in 1979 when the Islamic Revolution occurred was 37 million; today it’s 75 million. Egypt’s was 40 million; today it’s 85 million. The stresses from more people, climate change and decades of environmental abuse in both countries can no longer be ignored or bought off.

On July 9, Iran’s former agriculture minister, Issa Kalantari, an adviser to Iran’s new president, Hassan Rouhani, spoke to this reality in the Ghanoon newspaper: “Our main problem that threatens us, that is more dangerous than Israel, America or political fighting, is the issue of living in Iran,” said Kalantari. “It is that the Iranian plateau is becoming uninhabitable. … Groundwater has decreased and a negative water balance is widespread, and no one is thinking about this.”

He continued: “I am deeply worried about the future generations. … If this situation is not reformed, in 30 years Iran will be a ghost town. Even if there is precipitation in the desert, there will be no yield, because the area for groundwater will be dried and water will remain at ground level and evaporate.” Kalantari added: “All the bodies of natural water in Iran are drying up: Lake Urumieh, Bakhtegan, Tashak, Parishan and others.” Kalantari concluded that the “deserts in Iran are spreading, and I am warning you that South Alborz and East Zagros will be uninhabitable and people will have to migrate. But where? Easily I can say that of the 75 million people in Iran, 45 million will have uncertain circumstances. … If we start this very day to address this, it will take 12 to 15 years to balance.”

In Egypt, soil compaction and rising sea levels have already led to saltwater intrusion in the Nile Delta; overfishing and overdevelopment are threatening the Red Sea ecosystem, and unregulated and unsustainable agricultural practices in poorer districts, plus more extreme temperatures, are contributing to erosion and desertification. The World Bank estimates that environmental degradation is costing Egypt 5 percent of gross domestic product annually.

But just as Mother Nature is demanding better governance from above in both countries, an emergent and empowered middle class, which first reared its head with the 2009 Green revolution in Iran and the 2011 Tahrir revolution in Egypt, is doing so from below. A government that just provides “order” alone in either country simply won’t cut it anymore. Order, drift and decay were tolerable when populations were smaller, the environment not so degraded, the climate less volatile, and citizens less technologically empowered and connected.

Both countries today need “order-plus” — an order that enables dynamism and resilience, and that can be built only on the rule of law, innovation, political and religious pluralism, and greater freedoms. It requires political and economic institutions that are inclusive and “sustainable,” in both senses of that word. Neither country can afford the old line that Hosni Mubarak used for so many years when addressing American leaders: “After me comes the flood, so you’d better put up with my stale, plodding but stable leadership, otherwise you’ll get the Muslim Brotherhood.”

That is so 1970s. As Karim Sadjadpour, an Iran expert at the Carnegie Endowment, puts it: In the Middle East today “it’s no longer ‘After me, the flood’ — Après moi, le déluge — but ‘After me, the drought.’ ” Syria’s revolution came on the heels of the worst drought in its modern history, to which the government failed to respond.

Iran’s Islamic leadership seems to realize that it cannot keep asking its people to put up with crushing economic sanctions to preserve a nuclear weapons option. Mother Nature and Iran’s emergent middle classes require much better governance, integrated with the world. That’s why Iran is seeking a nuclear deal now with Washington.

And that’s why two of the most interesting leaders to watch today are President Rouhani of Iran and Egypt’s new military strongman, Gen. Abdul Fattah el-Sisi. Both men rose up in the old order, but both men were brought into the top leadership by the will of their emergent middle classes and newly empowered citizens, and neither man will be able to maintain order without reforming the systems that produced them — making them more sustainable and inclusive. They have no choice: too many people, too little oil, too little soil.

And pay attention: What Mother Nature and these newly empowered citizens have in common is that they can both set off a wave — a tsunami — that can overwhelm them and they will never see it coming.

by Prof. Andy Pitman, via The Conversation

Prof. Any Pitman, Univ. of NSW

On September 27 2013 the 5th Assessment Report by the Intergovernmental Panel on Climate Change (IPCC) will be released.

One part of this report will address the so-called “warming hiatus”. This is the argument that warming has stopped, with the further assertion in some quarters that we therefore have nothing to worry about in the future.

It is a fact, based on observations of air temperature, that the rate of global warming measured as surface air temperature has slowed over the past 15 years. The last decade is still the warmest in the past 150 years.

If you measure global heat content then global warming has not slowed. If you measure other indices including sea level rise or ocean temperatures or sea ice cover global warming has not slowed.

However, the warming trend in air temperatures has slowed over the last 15 years. There is a great deal of interest in this “hiatus” in the sense of whether it points to some fundamental error in climate science.

The 5th Assessment Report by the IPCC explains the slowing in the rate of global warming in roughly equal terms as the consequence of reduced radiative forcing (the difference between radiative energy that hits the earth and energy radiated back to space), increased heat uptake by the oceans and natural variability.

The reduced radiative forcing (the amount of energy available to drive the climate system) is due to the recent solar minimum (a period of low solar activity), and volcanic and anthropogenic aerosols (these are particles such as sulphur and soot, which block some radiation from hitting the earth).

The slowing in the rate of warming over the last 15 years is not in the least surprising. We have seen a combination of the solar minimum, anthropogenic aerosol emissions and back-to-back La Niñas.

What is surprising – and what is deeply concerning to me and almost entirely missed in the media commentary – is that we have not cooled dramatically over the last 15 years.
Below is the global surface temperature graph – this comes from a NASA site but any other reputable temperature reconstruction makes similar points. Note that there were periods through the 20th century where combinations of aerosols from volcanoes and human sources, solar variability and natural variability led to very significant cooling.

Figure 1: Global surface temperature. NASA

Between about 1880 and 1890, temperatures cooled by about 0.4C. Between 1900 and 1910 temperatures cooled close to 0.3C. Between 1945 and 1950 temperatures cooled about 0.35C. Between 1962 and 1965 temperatures cooled about 0.3C. There are other examples, but these were decade-scale cooling of 0.3C to 0.4C.

The most recent period of similar relevance starts with the extremely hot year, 1998. Since 1998, through to 2012, the temperatures cooled by 0.03C. However you choose to view the figure you simply have to conclude that natural variability, aerosols and solar variability have caused global cooling in the past of a scale that dwarfs anything that has occurred in the last 15 years.

So, here is what I think we should be genuinely concerned about.

Given the double-dip La Niña, coupled with the solar minimum and coupled with the high aerosol output from some developing nations, the question in the minds of some climate scientists is not “why has it cooled?”, because it has not cooled in any significant sense and the climatologically significant trends (calculated over 30 years) remain upwards.
Indeed, despite a suite of forcings that should have led to cooling, we still had the warmest decade in the observational record.

So, the question is, given it did cool several times in the historical period under broadly parallel circumstances in terms of the forcing, why has it not cooled since 1998 by 0.3C or 0.4C, and how come we broke the records for the warmest decade?

There has been time (its 15 years while previous cooling occurred in 10 years) for cooling of 0.3C or 0.4C to have occurred. There really is a case to argue that we should have cooled to close to the values measured in around 1990 and definitely not broken the record for the warmest decade on record.

A plausible answer is that we have underestimated the climate sensitivity.

We know, for certain, that aerosols, natural variability and solar variability have cooled the climate in the past. This time, they have not.

One way that this makes sense is if climate scientists have underestimated how dominant CO₂ and other greenhouse gases are in warming the climate. In other words, CO₂ and other greenhouse gases are countering the cooling effects of natural variability by much more than we anticipated.

If correct, this means that the capacity of CO₂ and other greenhouse gases to accelerate warming – once natural variability, solar variability and aerosols decline in influence – has been underestimated.

A second possible explanation is that the warming by CO₂ has led to a sufficiently different climate system that natural variability now functions differently. This seems extremely unlikely but is certainly anything but comforting.

If you see the slowing of warming over the last 15 years as a hint that climate scientists might have been wrong and that global warming is less of a problem than predicted, you are very likely being lulled into a false sense of security.

The lack of cooling of 0.3C or 0.4C since 1998 is most easily explained by the effect of increasing CO₂ and other greenhouse gases masking the cooling that would otherwise have occurred.

It follows that when we next see an El Niño, and the solar cycle is more average, or if developing countries clean up their aerosol emissions, we will see an acceleration of warming rates observed prior to 1998.

In short, the slowing of warming rates since 1998 is not a good news story. It is very likely a hint that climate scientists have underestimated the sensitivity of climate to increasing CO₂ and the slowing of warming is lulling us into a very false sense of security.