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Tag Archive: 1.5C

  1. Small-scale farmers in a 1.5°C future: The importance of local social dynamics as an enabling factor for implementation and scaling of climate-smart agriculture

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    • Small-scale farmers can contribute to a 1.5°C future while adapting to climate change.
    • By using adaptation as an entry point, climate-smart ag (CSA) mitigation co-benefits can help reduce GHG.
    • Social capital generated through social networks can promote CSA scaling.
    • Social networks enable interactions across scales that can support spreading of CSA.
    April 2018 Current Opinion in Environmental Sustainability
    Climate-smart agriculture (CSA) has the potential to help farmers implement both adaptation and mitigation practices. The mitigation aspect of CSA is often not considered by farmers due to a high discount rate and, as such, adaptation is usually the priority concern…
    …Approaches such as climate-smart agriculture (CSA) [8] are intended to help to reorient agricultural systems to support food security under conditions of climate change and increased climate variability. Successful CSA consists of simultaneously achieving three goals or pillars according to FAO [8]: (i) sustainably increasing agricultural productivity to support equitable increases in incomes, food security and development; (ii) adapting and building resilience to climate change from the farm to national levels; and (iii) reducing or removing greenhouse gas (GHG) emissions where possible…

    …In agricultural research, scaling out is the objective to reach a wide number of farmers with improved practices [14], and scaling up occurs when institutional buy-in and policies are influenced at higher levels [15]. Though there are a wide array of challenges to scaling CSA, many of these can be addressed through technical, social, economic, and policy innovations [16]. Many of these are social processes and, though much of the work on adaptation has built on the ideas of capabilities associated with the “five capitals” (financial, natural, human, physical and social), we have perhaps lost sight of many of the complexities and nuances associated with social capital in particular [17]….

    ….In order to achieve a 1.5°C scenario, consideration of the characteristics of local networks should figure into the design of any community engagement effort [26••; 51 ;  52]. This is especially the case now that the call for “mainstreaming” synergistic adaptation-mitigation practices into development policy has become part of the standard refrain [24 ;  53]. With an understanding of how adaptation strategies synergize across scale as a function of the existing networks, a goal should be to leverage community strengths and design strategies that maximize mitigation as a direct co-benefit of the implementation of adaptation practices. This is even more important where “…motivation to pursue long-term, broad-based plans, and/or to respond to community priorities, may be constrained” [54••] (p.17). An examination of local networks thus has the potential to serve as something of a first pass for establishing both the relevance and transferability of different CSA practices at different scales, while simultaneously serving as basis for designing the corresponding institutional arrangements that will better facilitate the uptake of practices with mitigation co-benefits depending on local socio-ecological circumstances [49]…

    …We argue that achieving a 1.5°C scenario requires small-scale farmers’ contributions through the implementation of strategies that provide mitigation co-benefits and synergies linked to adaptation but that additional understanding of farmers network context is a critical first step. A 1.5°C future could consist of small-scale farmers increasing their resilience through low carbon adaptation to climate change, contributing to the global mitigation efforts. However, this will require CSA options to be implemented widely and rapidly, meaning uptake by most of the small-scale farmers as soon as possible. Explicit acknowledgement of how social capital and networks operate in relation to climate challenges thus has the potential to be a critical ingredient when designing and implementing CSA at scale.

    Social networks are likely a key to facilitate scaling up and out processes by enabling individuals and institutions to interact across scales, guiding their decision making processes [34••], and building social capital that spreads CSA strategies….

    Deissy Martinez-Baron, Guillermo Orjuela, Giampiero Renzoni, Ana María Loboguerrero Rodríguez, Steven D Prager.

    Current Opinion in Environmental Sustainability, Volume 31, April 2018, Pages 112–119,
  2. Fighting Climate Change? We’re Not Even Landing a Punch – Opinion

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    • Decades of diplomatic efforts to stem global warming have proven ineffectual because too many strategies have been taken off the table.
    • But what definitely won’t suffice is a climate strategy built out of wishful thinking: the proposition that countries can be cajoled and prodded into increasing their ambition to cut emissions further, and that laggards can be named and shamed into falling into line.
    • There is no momentum for investing in carbon capture and storage, since it could be seen as condoning the continued use of fossil fuels. Nuclear energy, the only source of low-carbon power ever deployed at the needed scale, is also anathema. Geoengineering, like pumping aerosols into the atmosphere to reflect the sun’s heat back into space, is another taboo. But eventually, these options will most likely be on the table, as the consequences of climate change come more sharply into focus…

    By EDUARDO PORTER January 23 2018 read full NYTimes column here

    In 1988, when world leaders convened their first global conference on climate change in Toronto, the Earth’s average temperature was a bit more than half a degree Celsius above the average of the last two decades of the 19th century, according to measurements by NASA.

    Global emissions of greenhouse gases amounted to the equivalent of some 30 billion tons of carbon dioxide a year — excluding those from deforestation and land use. Worried about its accumulation, the gathered scientists and policymakers called on the world to cut CO2 emissions by a fifth.

    That didn’t happen, of course. By 1997, when climate diplomats from the world’s leading nations gathered to negotiate a round of emissions cuts in Kyoto, Japan, emissions had risen to some 35 billion tons and the global surface temperature was roughly 0.7 degrees Celsius above the average of the late 19th century.

    It took almost two decades for the next breakthrough. When diplomats from virtually every country gathered in Paris just over two years ago to hash out another agreement to combat climate change, the world’s surface temperature was already about 1.1 degrees Celsius above its average at the end of the 1800s. And greenhouse gas emissions totaled just under 50 billion tons….


    …Climate diplomats in Paris didn’t merely reassert prior commitments to keep the world’s temperature less than 2 degrees above that of the “preindustrial” era — a somewhat fuzzy term that could be taken to mean the second half of the 19th century. Hoping to appease island nations like the Maldives, which are likely to be swallowed by a rising ocean in a few decades, they set a new “aspirational” ceiling of 1.5 degrees.

    To stick to a 2 degree limit, we would have to start reducing global emissions for real within about a decade at most — and then do more. Half a century from now, we would have to figure out how to suck vast amounts of carbon out of the air. Keeping the lid at 1.5 degrees would be much harder still.

    And yet, when experts tallied the offers made in Paris by all the countries in the collective effort, they concluded that greenhouse gas emissions in 2030 would exceed the level needed to remain under 2 degrees by 12 to 14 billion tons of CO2.

    Are there better approaches? The “climate club” proposed by the Yale University economist William Nordhaus has the advantage of including an enforcement device, which current arrangements lack: countries in the club, committed to reducing carbon emissions, would impose a tariff on imports from nonmembers to encourage them to join.

    Martin Weitzman of Harvard University supports the idea of a uniform worldwide tax on carbon emissions, which might be easier to agree on than a panoply of national emissions cuts. One clear advantage is that countries could use their tax revenues as they saw fit.

    Mr. Barrett argues that the Paris agreement could be supplemented with narrower, simpler deals to curb emissions of particular gases — such as the 2016 agreement at a 170-nation meeting in Kigali, Rwanda, to reduce hydrofluorocarbon emissions — or in particular industries, like aviation or steel.

    Maybe none of this would work. The climate club could blow up if nonmembers retaliated against import tariffs by imposing trade barriers of their own. Coordinating taxes around the world looks at least as difficult as addressing climate change. And Mr. Barrett’s proposal might not deliver a breakthrough on the scale necessary to move the dial.


    But what definitely won’t suffice is a climate strategy built out of wishful thinking: the proposition that countries can be cajoled and prodded into increasing their ambition to cut emissions further, and that laggards can be named and shamed into falling into line.

    Inveigled by three decades of supposed diplomatic progress — coupled with falling prices of wind turbines, solar panels and batteries — the activists, technologists and policymakers driving the strategy against climate change seem to have concluded that the job can be done without unpalatable choices. And the group is closing doors that it would do best to keep open.

    There is no momentum for investing in carbon capture and storage, since it could be seen as condoning the continued use of fossil fuels. Nuclear energy, the only source of low-carbon power ever deployed at the needed scale, is also anathema. Geoengineering, like pumping aerosols into the atmosphere to reflect the sun’s heat back into space, is another taboo.

    But eventually, these options will most likely be on the table, as the consequences of climate change come more sharply into focus. The rosy belief that the world can reduce its carbon dependency over a few decades by relying exclusively on the power of shame, the wind and the sun will give way to a more realistic understanding of possibilities.

  3. Potential Global Warming From Doubling of CO2 Reduced from 4.5C to 2.8C; critical for guiding efforts to stay under 2C increase since pre-industrial times

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    If one is the loneliest number, two is the most terrifying. Humanity must not pass a rise of 2 degrees Celsius in global temperature from pre-industrial levels, so says the Paris climate agreement. Cross that line and the global effects of climate change start looking less like a grave situation and more like a catastrophe.

    …today in the journal Nature, researchers claim they’ve reduced the uncertainty in a key metric of climate change by 60 percent, narrowing a range of potential warming from 3°C to 1.2°C.

    …The metric is called equilibrium climate sensitivity, but don’t let the name scare you. “It’s essentially the amount of global warming we would predict if we just doubled the atmospheric carbon dioxide and let the atmosphere and climate come to equilibrium with the carbon dioxide,” says lead author Peter Cox, who studies climate system dynamics at the University of Exeter….

    ….the researchers say this means the probability of the ECS being less than 1.5°C—the Paris Climate Agreement’s super optimistic goal beyond the 2°C goal—is less than 3 percent. The upside, though, is they say this new estimate means the probability of the ECS passing 4.5°C is less than 1 percent.

    …It’s just that global climate change is an exceedingly complex problem. There’s no way any scientist can dig down into all the granular details—changes in vegetation, small-scale hydrology, every single weather event like a hurricane or tornado. So what scientists do is find simplified descriptions of these small-scale events….

    Peter M. Cox, Chris Huntingford & Mark S. Williamson. Emergent constraint on equilibrium climate sensitivity from global temperature variability. Nature 553, 319–322 (18 January 2018). doi:10.1038/nature25450

    ABSTRACT: Equilibrium climate sensitivity (ECS) remains one of the most important unknowns in climate change science. ECS is defined as the global mean warming that would occur if the atmospheric carbon dioxide (CO2) concentration were instantly doubled and the climate were then brought to equilibrium with that new level of CO2. Despite its rather idealized definition, ECS has continuing relevance for international climate change agreements, which are often framed in terms of stabilization of global warming relative to the pre-industrial climate. However, the ‘likely’ range of ECS as stated by the Intergovernmental Panel on Climate Change (IPCC) has remained at 1.5–4.5 degrees Celsius for more than 25 years1. The possibility of a value of ECS towards the upper end of this range reduces the feasibility of avoiding 2 degrees Celsius of global warming, as required by the Paris Agreement. Here we present a new emergent constraint on ECS that yields a central estimate of 2.8 degrees Celsius with 66 per cent confidence limits (equivalent to the IPCC ‘likely’ range) of 2.2–3.4 degrees Celsius. Our approach is to focus on the variability of temperature about long-term historical warming, rather than on the warming trend itself. We use an ensemble of climate models to define an emergent relationship2 between ECS and a theoretically informed metric of global temperature variability. This metric of variability can also be calculated from observational records of global warming3, which enables tighter constraints to be placed on ECS, reducing the probability of ECS being less than 1.5 degrees Celsius to less than 3 per cent, and the probability of ECS exceeding 4.5 degrees Celsius to less than 1 per cent.

    And for more perspective on this see:

    A ‘new’ measurement of climate sensitivity?



  4. Broader range of scenarios needed for policymakers to limit warming to under 2°C

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    • a broader range of scenarios is needed to support international policymakers in the target of limiting climate change to under 2°C above pre-industrial levels, and to avoid potential negative environmental and social consequences of carbon dioxide removal on a massive scale.
    • 87% of the scenarios in the IPCC 5th Assessment Report that limit climate change to less than 2°C rely heavily on negative emissions in the second half of the century, with most of the carbon dioxide removal coming from a suite of technologies known as Bioenergy with Carbon Capture and Storage (BECCS)
    • massive implementation of these type of land-based carbon dioxide removal strategies would have impacts on both the environment and the food system, with previous research showing trade-offs for food security and environmental conservation.
    • reliance on future negative emissions to achieve climate goals may also fail to account for feedbacks in the climate system such as methane release from thawing permafrost, which are not yet fully understood

    January 12, 2018 International Institute for Applied Systems Analysis (IIASA) read full ScienceDaily article here

    A new article lays the groundwork for alternative climate mitigation scenarios that place less reliance on unproven negative emissions technologies in the future.

    …”Many currently used emissions pathways assume that we can slowly decrease fossil fuel emissions today and make up for it later with heavy implementation of negative emissions technologies,” says IIASA Ecosystems Services and Management Program Director Michael Obersteiner, lead author of the article. “This is a problem because it assumes we can put the burden on future generations — which is neither a realistic assumption nor is it morally acceptable from an intergenerational equity point of view.

    ….The researchers present four archetype scenarios that incorporate a broader range of potential mitigation options. These include:

    • Major reliance on carbon dioxide removal in the future, the current archetype of many existing scenarios for achieving the 2°C or more stringent 1.5°C target.
    • Rapid decarbonization starting immediately, and halving every decade as proposed in a recent Science commentary coauthored by IIASA researchers.
    • Earlier implementation of carbon dioxide removal technologies, and phasing out by the end of the century
    • Consistent implementation of carbon dioxide removal from now until the end of the century.

    Under all these scenarios, current country commitments under the Paris Agreement would not be sufficient to achieve the required cuts, the researchers say…

    ….IIASA researcher Fabian Wagner, another study coauthor adds, “In this paper we have shown that negative emission technologies may not only be an asset but also an economic burden if not deployed with care. We as scientists need to be careful when we communicate to policymakers about how realistic different scenarios might be. When we present scenarios that require the world to convert an amount of land equivalent to all today’s cropland to energy plantations, alarm bells should go off.

    Michael Obersteiner, Johannes Bednar, Fabian Wagner, Thomas Gasser, Philippe Ciais, Nicklas Forsell, Stefan Frank, Petr Havlik, Hugo Valin, Ivan A. Janssens, Josep Peñuelas, Guido Schmidt-Traub. How to spend a dwindling greenhouse gas budget. Nature Climate Change, 2018; 8 (1): 7 DOI: 10.1038/s41558-017-0045-1

  5. Study predicts a significantly drier world if global warming reaches 2ºC

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    • Limiting warming to under 1.5ºC would dramatically reduce the fraction of the Earth’s surface that undergoes such changes.

    January 1, 2018 University of East Anglia Read full ScienceDaily article here

    New research predicts a significantly drier world if global warming reaches 2ºC. Over a quarter of the world’s land could become significantly drier and the change would cause an increased threat of drought and wildfires.

    The change would cause an increased threat of drought and wildfires.

    But limiting global warming to under 1.5C would dramatically reduce the fraction of the Earth’s surface that undergoes such changes. Areas which would most benefit from keeping warming below 1.5ºC include Central America, Southern Europe, Southern Australia, parts of South East Asia, and Southern Africa.

    …Dr Chang-Eui Park….one of the authors of the study, said: “Aridification is a serious threat because it can critically impact areas such as agriculture, water quality, and biodiversity. It can also lead to more droughts and wildfires — similar to those seen raging across California.

    “Another way of thinking of the emergence of aridification is a shift to continuous moderate drought conditions, on top of which future year-to-year variability can cause more severe drought.

    Chang-Eui Park, et al. Keeping global warming within 1.5 °C constrains emergence of aridification. Nature Climate Change 8, 70–74 (2018). doi:10.1038/s41558-017-0034-4

  6. The role of cities in climate change: massive upscaling of local climate policies key to achieving 1.5 °C target

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    • Local governments are crucial actors in the multi-level climate governance system.
    • A massive upscaling of local climate policies is key to achieving the 1.5 °C target.
    • Local climate action must go hand in hand with higher-level governance initiatives.

    Fuhr, H. et al. The role of cities in multi-level climate governance: local climate policies and the 1.5 °C target. Current Opinion in Environmental Sustainability. Volume 30, February 2018, Pages 1-6.  Published on line Nov 2017

  7. Climate change impacts already locked in, but the worst can still be avoided

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    November 16, 2017 University of Exeter Read full ScienceDaily article here

    Some impacts of global warming — such as sea level rise and coastal flooding — are already locked in and unavoidable, according to a major research project.
    Global temperatures have already risen by around 1°C, and a further 0.5°C warming is expected. The full impacts of current warming have not yet been seen, since ice sheets and oceans take many decades to fully react to higher temperatures.

    But more severe impacts can still be avoided if global greenhouse gas emissions are reduced.

    More than 50 scientists from 16 institutions in 13 countries have worked on the HELIX project (High-End Climate Impacts and Extremes), which has just finished after four years. The project examined the possible effects of warming of 1.5°C, 2°C, 4°C and 6°C compared to pre-industrial levels.

    Even with rapid cuts in global greenhouse gas emissions keeping warming below 2°C, sea levels could rise by 0.5m by the end of the 21st Century, particularly affecting small island states and low-lying countries. HELIX calculations suggest this could impact 2.5 million in Bangladesh….

  8. Scientific reticence on climate change- Jim Hansen

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    26 October 2017  by James Hansen read this draft discussion and find links to other papers here

    I am writing Scientific Reticence and the Fate of Humanity in response to a query from the editor of Atmospheric Chemistry and Physics who handled Ice Melt, Sea Level Rise and Superstorms. That paper, together with Young People’s Burden makes the case for a low global warming target and the urgency of phasing out fossil fuel emissions. We argue that global warming of 2°C , or even 1.5°C, is dangerous, because these levels are far above Holocene temperatures and even warmer than best estimates for the Eemian, when sea level reached 6-9 meters (20-30 feet) higher than today. Earth’s history shows that sea level adjusts to changes in global temperature. We conclude that eventual sea level rise of several meters could be locked in, if rapid emission
    reductions do not begin soon, and could occur within 50-150 years with the extraordinary climate forcing of continued “business-as-usual” fossil fuel emissions….
  9. How Improved Land Use Can Contribute to the 1.5°C Goal of the Paris Agreement

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    • The goals of the Paris Agreement cannot be met without
      significant contributions from the land sector, including
      supply-side measures in forestry and agriculture, and demand-
      side measures related to healthier diets and reduced food waste.
    • Through significant emissions reductions and carbon removals, the
      land sector can contribute about 25 percent of the progress needed
      to meet the 1.5°C goal formulated under the Paris Agreement.
    • Land-sector emissions have to peak by 2020 and become net-zero
      by 2040–50 and net-negative thereafter.

    October 2017 Read full ClimateFocus article and report here

    Climate Focus’ How Land Use Can Contribute to the 1.5°C Goal of the Paris Agreement develops a roadmap of action for the land-use sector to meet its necessary contribution to the Paris Agreement. The analysis relies on a modelling of land-sector development trajectories optimizing least-cost pathways, a bottom-up assessment of mitigation potentials, and a correction of potentials for political feasibility. The Global Biosphere Management Integrated Assessment Model, a partial-equilibrium model developed by the International Institute for Applied Systems Analysis, formed the basis of our modelling.

    We determined the 40 countries with the highest technical mitigation potential and assessed the feasibility of mitigation action based on their political will and ability to realize this potential. Finally, we outlined 10 priority actions to reduce the land-use sector’s contribution to global warming. The actions range from avoided deforestation, restoration of forests, to diet shifts and reduced food waste.

    …We developed a roadmap of action that relies on:

    • effective forest protection (reduced deforestation)
    • enhanced restoration
    • sustainable forest management
    • halting peatland burning
    • peatland restoration
    • a shift to healthier diets
    • reduced food waste and losses
    • enhanced soil carbon sequestration
    • increased efficiency of synthetic fertilizer production and use
    • reduced emissions from rice paddies
    • reduced emissions from livestock (enteric fermentation)
  10. Deforestation has double the effect on global warming than previously thought

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    • Even if all fossil fuel emissions are eradicated, if current rates of deforestation in the tropics continue through to 2100 then there will still be a 1.5 degree Celsius increase in global temperature
    • While carbon dioxide emissions from energy use must be the primary target of climate change mitigation efforts, land use and land cover change (LULCC) also represent an important source of climate forcing.
    • Tackling deforestation should be higher on the climate change agenda.


    In the fight against climate change, much of the focus rests on reducing our dependence on fossil fuels and developing alternative energy sources. However, the results of a new study suggest that far more attention should be paid to deforestation and how the land is used subsequently – the effects of which make a bigger contribution to climate change than previously thought.

    The research, conducted by Cornell University and published in the journal Environmental Research Letters,shows just how much this impact has been underestimated. Even if all fossil fuel emissions are eradicated, if current rates of deforestation in the tropics continue through to 2100 then there will still be a 1.5 degree Celsius increase in global temperature….

    Natalie M Mahowald et al. Are the impacts of land use on warming underestimated in climate policy? Environmental Research Letters. August 2017. DOI: 10.1088/1748-9326/aa836d

    Abstract: While carbon dioxide emissions from energy use must be the primary target of climate change mitigation efforts, land use and land cover change (LULCC) also represent an important source of climate forcing. In this study we compute time series of global surface temperature change separately for LULCC and non-LULCC sources (primarily fossil fuel burning), and show that because of the extra warming associated with the co-emission of methane and nitrous oxide with LULCC carbon dioxide emissions, and a co-emission of cooling aerosols with non-LULCC emissions of carbon dioxide, the linear relationship between cumulative carbon dioxide emissions and temperature has a two-fold higher slope for LULCC than for non-LULCC activities. Moreover, projections used in the Intergovernmental Panel on Climate Change (IPCC) for the rate of tropical land conversion in the future are relatively low compared to contemporary observations, suggesting that the future projections of land conversion used in the IPCC may underestimate potential impacts of LULCC. By including a “business as usual” future LULCC scenario for tropical deforestation, we find that even if all non-LULCC emissions are switched off in 2015, it is likely that 1.5°C of warming relative to the preindustrial era will occur by 2100. Thus, policies to reduce LULCC emissions must remain a high priority if we are to achieve the low to medium temperature change targets proposed as a part of the Paris Agreement. Future studies using integrated assessment models and other climate simulations should include more realistic deforestation rates and the integration of policy that would reduce LULCC emissions.