Energy and Meteorology: Partnership for the Future

Gunasekera, Don; Troccoli, Alberto; Boulahya, Mohammed Sadeck

doi:10.1007/978-1-4614-9221-4_24

“…For the moment, decadal prediction concentrates on ensemble mean change in variables that show skill in climate models, whereas the prospect of non-gradual change carries the greater risk. Under this type of framing, climate services remain supply driven rather than demand driven (Gunasekera et al, 2014;Street, 2016). Projections of mean change also overlook the considerable literature on scenarios that have arisen because of the failure of multi-year predictions of mean change in systems that exhibit considerable non-linearity (Wack, 1985a, b;Börjeson et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Reconciling the signal and noise of atmospheric warming on decadal timescales

Jones

¹

,

Ricketts

²

2017

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Interactions between externally forced and internally generated climate variations on decadal timescales is a major determinant of changing climate risk. Severe testing is applied to observed global and regional surface and satellite temperatures and modelled surface temperatures to determine whether these interactions are independent, as in the traditional signal-to-noise model, or whether they interact, resulting in step-like warming. The multistep bivariate test is used to detect step changes in temperature data. The resulting data are then subject to six tests designed to distinguish between the two statistical hypotheses, h step and h trend . Test 1: since the mid-20th century, most observed warming has taken place in four events: in 1979/80 and 1997/98 at the global scale, 1988/89 in the Northern Hemisphere and 1968-70 in the Southern Hemisphere. Temperature is more step-like than trend-like on a regional basis. Satellite temperature is more step-like than surface temperature. Warming from internal trends is less than 40 % of the total for four of five global records tested (1880-2013/14). Test 2: correlations between step-change frequency in observations and models are 0.32 (CMIP3) and 0.34 (CMIP5). For -98), the correlation increases to 0.78. Test 3: steps and shifts (steps minus internal trends) from a 107-member climate model ensemble explain total warming and equilibrium climate sensitivity better than internal trends. Test 4: in three regions tested, the change between stationary and non-stationary temperatures is step-like and attributable to external forcing. Test 5: step-like changes are also present in tide gauge observations, rainfall, ocean heat content and related variables. Test 6: across a selection of tests, a simple stepladder model better represents the internal structures of warming than a simple trend, providing strong evidence that the climate system is exhibiting complex system behaviour on decadal timescales. This model indicates that in situ warming of the atmosphere does not occur; instead, a store-and-release mechanism from the ocean to the atmosphere is proposed. It is physically plausible and theoretically sound. The presence of step-like -rather than gradual -warming is important information for characterising and managing future climate risk.Published by Copernicus Publications on behalf of the European Geosciences Union.

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“…For the moment, decadal prediction concentrates on ensemble mean change in variables that show skill in climate models, whereas the prospect of non-gradual change carries the greater risk. Under this type of framing, climate services remain supply driven rather than demand driven (Gunasekera et al, 2014;Street, 2016). Projections of mean change also overlook the considerable literature on scenarios that have arisen because of the failure of multi-year Earth Syst.…”

Section: Discussionmentioning

confidence: 99%

Supplementary material to "Reconciling the signal and noise of atmospheric warming on decadal timescales"

Jones¹,

Ricketts²

2016

Preprint

0

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Interactions between externally forced and internally generated climate variations on decadal timescales is a major determinant of changing climate risk. Severe testing is applied to observed global and regional surface and satellite temperatures and modelled surface temperatures to determine whether these interactions are independent, as in the traditional signal-to-noise model, or whether they interact, resulting in step-like warming. The multistep bivariate test is used to detect step changes in temperature data. The resulting data are then subject to six tests designed to distinguish between the two statistical hypotheses, h step and h trend. Test 1: since the mid-20th century, most observed warming has taken place in four events: in 1979/80 and 1997/98 at the global scale, 1988/89 in the Northern Hemisphere and 1968-70 in the Southern Hemisphere. Temperature is more step-like than trend-like on a regional basis. Satellite temperature is more step-like than surface temperature. Warming from internal trends is less than 40 % of the total for four of five global records tested (1880-2013/14). Test 2: correlations between step-change frequency in observations and models (1880-2005) are 0.32 (CMIP3) and 0.34 (CMIP5).

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“…Basically, meteorological factors are short-term influences, while climatic factors are long-term ones [ 26 , 27 ]. However, considering energy security, which is a long-term issue [ 28 ], both factors affect use of renewables, because climate change affects meteorological conditions. The second point is diversifying energy import, including tradeoffs between importing and domestic supply.…”

Section: Introductionmentioning

confidence: 99%

Energy Structure and Energy Security under Climate Mitigation Scenarios in China

Matsumoto

¹

2015

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This study investigates how energy structure and energy security in China will change in the future under climate mitigation policy scenarios using Representative Concentration Pathways in a computable general equilibrium model. The findings suggest that to reduce greenhouse gas emissions, China needs to shift its energy structure from fossil fuel dominance to renewables and nuclear. The lower the allowable emissions, the larger the shifts required. Among fossil fuels, coal use particularly must significantly decrease. Such structural shifts will improve energy self-sufficiency, thus enhancing energy security. Under the policy scenarios, energy-source diversity as measured by the Herfindahl Index improves until 2050, after which diversity declines because of high dependence on a specific energy source (nuclear and biomass). Overall, however, it is revealed that energy security improves along with progress in climate mitigation. These improvements will also contribute to the economy by reducing energy procurement risks.

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Energy and Meteorology: Partnership for the Future

Cited by 3 publications

References 13 publications

Reconciling the signal and noise of atmospheric warming on decadal timescales

Reconciling the signal and noise of atmospheric warming on decadal timescales

Supplementary material to "Reconciling the signal and noise of atmospheric warming on decadal timescales"

Energy Structure and Energy Security under Climate Mitigation Scenarios in China

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Energy and Meteorology: Partnership for the Future

Cited by 3 publications

References 13 publications

Reconciling the signal and noise of atmospheric warming on decadal timescales

Reconciling the signal and noise of atmospheric warming on decadal timescales

Supplementary material to &quot;Reconciling the signal and noise of atmospheric warming on decadal timescales&quot;

Energy Structure and Energy Security under Climate Mitigation Scenarios in China

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Supplementary material to "Reconciling the signal and noise of atmospheric warming on decadal timescales"