Scientists find signals of climate 'tipping points' in the past - relevance for carbon-negative energy

In the Earth’s history, periods of relatively stable climate have often been interrupted by sharp transitions to a contrasting state. For instance, glaciation periods typically ended suddenly. About 34 million years ago the Earth’s long lasting tropical state in which most recent life forms evolved, shifted abruptly and irreversibly to a cooler state with ice caps. This shift is known as the "Greenhouse-Icehouse-Transition". Scientists long suspected that such sharp transitions - called "Abrupt Climate Change" (ACC) events - might be related to tipping points where positive feedback mechanisms lead to self-propelling change. They have now found typical warning signals that preceded the onset of such ACC events in the past. The findings are highly relevant to the current debate about how to mitigate climate change, and to the question of whether we should prepare for ACC.

The threat of ACC events is very important to the bioenergy community, because it is widely recognized that only biomass-based energy systems are capable of mitigating such potential cataclysms. Scientists from the Abrupt Climate Change Strategy group (ACCS) were tasked to develop several scenarios and technological pathways that show how we can deliver carbon-negative energy which rapidly takes CO2 out of the atmosphere and brings us back to pre-industrial atmospheric CO2 levels - possibly our only shot at reversing approaching ACC events without radically powering down our societies (previous post). Carbon-negative bioenergy yields negative emissions, whereas all other energy technologies result in more carbon dioxide ending up in the atmosphere (illustration, click to enlarge). Even a rapid shift to carbon-neutral energy technologies would not suffice to reverse the threat of ACC.

To describe the tipping points which cause ACC events, researchers often use the example of the ice-albedo feedback. If ice caps melt, more sunlight is absorbed by the darker surface that is exposed. This causes further warming. Eventually, a rapid warming process that is irreversible and self-sustaining occurs. Although such mechanisms are well known, it was difficult so far to determine whether these feedbacks were strong enough to cause "tipping points".

A team of Dutch and German scientists around Marten Scheffer from Wageningen University and Hermann Held from the Potsdam Institute for Climate Impact Research has now analyzed the geological records of eight ancient events of abrupt climate change. These are the end of the greenhouse Earth, the end of the Younger Dryas, the Bølling-Alleröd-Transition, the desertification of North Africa and the ends of four glaciation periods.

In an article in the current online edition of the Proceedings of the National Academy of Sciences the researchers now report that sharp climatic shifts in the past were systematically preceded by subtle alterations in fluctuation patterns. These alterations are proven to be characteristic of systems approaching tipping points. This finding supports the theory that the sharp climatic shifts in the past have happened as the Earth system went over critical thresholds where self-catalyzing change pushed it further towards a contrasting state.

The demonstration of tipping points has implications for the thinking about current climate change, the authors state. The well known projections by the Intergovernmental Panel on Climate Change (IPCC) are based on the assumption of rather linear change:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: carbon-negative energy :: bio-energy with carbon storage :: negative emissions :: abrupt climate change ::

But although some feedbacks in the Earth system may dampen change, the new results imply that we should also consider the possibility that the climate will cross a tipping point after which changes will be amplified and end up in abrupt alterations.

Whether climate as a whole is now approaching a tipping point is difficult to judge with the new techniques. This is because human influence is simply too fast to generate data records long enough for the detection method. However, for certain parts of the climate system the method may be readily applicable to predict future abrupt change.

References:
Vasilis Dakos, Marten Scheffer, Egbert H. van Nes, Victor Brovkin, Vladimir Petoukhov, and Hermann Held, "Slowing down as an early warning signal for abrupt climate change", PNAS early online publication, September 2008 [not yet online].

P. Read and J. R. Lermit, "Bio-energy with carbon storage(BECS): a sequential decision approach to the threat of abrupt climate change" [*.pdf], Energy, November 2005, vol. 30, no14, pp. 2654-2671

Biopact: Research warns 'dangerous climate change' may be imminent - carbon negative bioenergy now - May 31, 2007

Biopact: Carbon-negative bioenergy making headway, at last - June 06, 2008

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Biofuels and biopharmaceuticals meet: scientists develop safe and inexpensive alternative to antibiotics in production of biotech products

Researchers at Sweden's Karolinska Institute and at the Royal Veterinary College (RVC) in London have developed a system that eliminates the need for antibiotics and resistance genes in the engineering of industrial and medical products. The method involves safer, less costly alternatives and is well suited for industrial production of many types of biofuels and biopharmaceuticals. The research has been published as an open access article in BMC Biotechnology.

Antibiotic resistance genes are widely used for selection of recombinant bacteria for use in biotechnology, but their use risks contributing to the spread of antibiotic resistance, particularly as biotechnology products move into the environment and the clinic. In particular, the practice is inappropriate for some intrinsically resistant bacteria and in vaccine production, and costly for industrial scale production. Non-antibiotic systems are available, but require mutant host strains, defined media or expensive reagents.

Gene targeting is the insertion of DNA into specific sites or genes within the genome of selected cells in order to alter gene expression for a particular purpose.

While working on gene targeting in bacteria, the researchers discovered that a well-known interaction between a cell membrane synthesis gene and the biocide triclosan could be exploited for strain selection. Surprisingly, triclosan selection performs better than conventional antibiotic selection:

We think this simple technology is well suited for industrial scale fermentations that produce a range of valuable products, including bio-fuels and bio-pharmaceuticals. More importantly, the new system is relatively safe and inexpensive, because the gene is native in all bacteria and triclosan is approved for use in many household applications. - Dr Liam Good, Royal Veterinary College and lead researcher on the project

energy :: sustainability :: biomass :: bioenergy :: biofuels :: bioproducts :: biopharmaceuticals :: biotechnology ::

The new cloning vector, pFab, enabled selection by triclosan at 1 μM. Interestingly, pFab out-performed the parent pUC19-ampicillin system in cell growth, plasmid stability and plasmid yield. Also, pFab was toxic to host cells in a way that was reversed by triclosan. Therefore, pFab and triclosan are toxic when used alone but in combination they enhance growth and plasmid production through a gene-inhibitor interaction.

The fabI-triclosan model system thus provides an alternative plasmid selection method based on essential gene over-expression, without the use of antibiotic-resistance genes and conventional antibiotics.

The research was carried out with Dr Shan Goh of the Department of Cell and Molecular Biology of the Karolinska Institute, Stockholm.

References:
Shan Goh and Liam Good, "Plasmid selection in Escherichia coli using an endogenous essential gene marker", BMC Biotechnology 2008, 8:61, doi:10.1186/1472-6750-8-61.

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South Korea Minister: "biomass most important of all renewables"

It is very rare for a policy maker to explicitly say which of the future energy sources he thinks will be the most important. Most politicians would prefer to remain technology neutral. But in South Korea, Knowledge & Economy Minister Lee Yoon-Ho was asked the question by parliament, requiring him to make a choice. His answer: biomass and bioenergy will be "the most important and useful amongst new sources of renewable energy for a significant time in the future".

The minister made the remarks on Tuesday in a plenary session of the parliamentary committee on knowledge and economy. Lee was answering Grand National Party lawmaker Kang Yong-seok’s questions on the efficiency of renewable energy sources.

The minister compared renewable technologies such as solar, wind, small hydro and biomass . The latter clearly stood out, even though Lee Yoon-Ho gave no list of reasons as to why he thinks this is so.

There are some obvious advantages to bioenergy, though, making his choice rather self-evident:

• biomass offers reliable baseloads, as it is stored solar energy; other renewables are intermittent and thus rely on an outside source of energy in order to deliver energy round the clock. Currently, there are no efficient energy storage options for wind or solar
• biomass is the only renewable energy source capable of providing renewable heat in an efficient manner (co-generation, district heating, household boilers); in many highly developed countries (like South Korea) heating is both the most difficult as well as the sector with the biggest need for renewable energy
  
• biomass can make use of existing infrastructures, such as coal and gas power plants and their fuel handling infrastructures, as well as gas pipelines and coal supply chain infrastructures
  
• biomass can be physically transported and traded, because it is stored solar energy. This makes it possible to plan and optimise energy production at sites that need reliable baseloads and where there is a lack of space for other renewables. Trading biomass also allows power producers to import fuels from countries where the production would yield major environmental or social benefits, or from places where a low-cost supply is available.
• a single source of biomass can be converted into a wide range of products, from green platform chemicals to liquid, gaseous and solid fuels; this flexibility gives energy crop growers a range of strategic options which can maximise value
• energy crops can help to restore the environment; they can be grown to perform key ecosystem services, such as curbing erosion and desertification, re-greening deforested areas, restoring soil health, and most importantly, sequestering carbon
• biomass can become carbon-negative, that is, systems can be designed that actively remove CO2 from the atmosphere (by geosequestering biogenic CO2 or by sequestering biochar in soils); all other renewables on the contrary remain carbon-positive over their lifecycle
• last but not least, biomass is by far the least costly of all renewables, easing the economic challenge of making a transition to clean energy and making it possible to serve the poor, who are always the first to suffer under higher energy prices
  

Obviously, the story of renewable energy is not one of pitting one technology against another one. On the contrary, renewables can be coupled to each other, and, with biomass delivering strong baseloads, replace all our fossil fuel based energy production in an affordable and efficient way [entry ends here].

Picture: Miscanthus x giganteus pellets, used in power plants in Europe.
energy :: sustainability :: biomass :: bioenergy :: solar :: wind power :: renewables :: intermittent :: baseload :: carbon-negative :: climate change ::

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