A Trillion Tons

Daedalus ◽  
2013 ◽  
Vol 142 (1) ◽  
pp. 8-25 ◽  
Author(s):  
Hal Harvey ◽  
Franklin M. Orr ◽  
Clara Vondrich
Keyword(s):  
Land Use ◽  
Energy Efficiency ◽  
Simulation Model ◽  
Carbon Emissions ◽  
Capital Stock ◽  
Technology Innovation ◽  
Energy Technology ◽  
Global Mean Temperature ◽  
The Impact ◽  
Global Mean

There is a consensus among scientists that stark dangers await in a world where the global mean temperature rises by more than about 2 degrees Celsius. That threshold corresponds to a collective human carbon emissions “budget” of around a trillion tons, of which half has been spent. This paper uses a new simulation model to look at strategies to stay within that budget, specifically assessing the impact of improvements in energy efficiency, aggressive deployment of renewables, and energy technology innovation. The simulations examine the timing of investments, turnover of capital stock, and the effect of learning on costs, among other factors. The results indicate that efficiency, renewables, and technology innovation are all required to keep humanity within the trillion-ton budget. Even so, these measures are not by themselves sufficient: changes in land use and a price on carbon emissions are also needed.

ECONOMIC AND PHYSICAL MODELING OF LAND USE IN GCAM 3.0 AND AN APPLICATION TO AGRICULTURAL PRODUCTIVITY, LAND, AND TERRESTRIAL CARBON

2014 ◽  
Vol 05 (02) ◽  
pp. 1450003 ◽  
Author(s):  
MARSHALL WISE ◽  
KATE CALVIN ◽  
PAGE KYLE ◽  
PATRICK LUCKOW ◽  
JAE EDMONDS
Keyword(s):  
Land Use ◽  
Crop Yield ◽  
Carbon Emissions ◽  
Crop Yields ◽  
Assessment Model ◽  
Agricultural Crop ◽  
Terrestrial Carbon ◽  
Global Change Assessment Model ◽  
The Impact

The release of the Global Change Assessment Model (GCAM) version 3.0 represents a major revision in the treatment of agriculture and land-use activities in a model of long-term, global human and physical Earth systems. GCAM 3.0 incorporates greater spatial and temporal resolution compared to GCAM 2.0. In this paper, we document the methods embodied in the new release, describe the motivation for the changes, compare GCAM 3.0 methods to those of other long-term, global agriculture-economy models and apply GCAM 3.0 to explore the impact of changes in agricultural crop yields on global land use and terrestrial carbon. In the absence of continued crop yield improvements throughout the century, not only are cumulative carbon emissions a major source of CO 2 emissions to the atmosphere, but bioenergy production remains trivial — land is needed for food. In contrast, the high crop yield improvement scenario cuts terrestrial carbon emissions dramatically and facilitates both food and energy production.

Heterogeneous impact of CO2 emissions on renewable energy technology innovation between oil importers and exporters

2020 ◽  
pp. 0958305X2092893
Author(s):  
Bai Liu ◽  
Yutian Liu ◽  
Ailian Zhang
Keyword(s):  
Renewable Energy ◽  
Solar Energy ◽  
Fixed Effects ◽  
Negative Binomial ◽  
Technology Innovation ◽  
Empirical Test ◽  
Negative Binomial Regression Model ◽  
Energy Technology ◽  
Renewable Energy Technology ◽  
The Impact

With the depletion of fossil energy and the rise of global temperature, it is urgent to use renewable energy to solve environmental problems. By studying the heterogeneous relationship between CO2 emissions and renewable energy technology innovation in different countries, we can find out the gap and something helpful to energy development. In the empirical test, we use the negative binomial regression model with fixed effects to study the impact of CO2 emissions on renewable energy technology innovation from 1997 to 2016. The research shows that impact is positive in oil-importing countries, but this relationship is not established in oil-exporting countries. In both oil importers and oil exporters, CO2 emissions have a positive effect on the solar energy technological innovation, however, the influence on the technology innovation of solar energy in oil exporters is more significant than that of renewable energy. Whether for oil importers or oil exporters, it can be more reasonable and effective to develop renewable energy by clarifying the impact of CO2 emissions on domestic renewable energy technology innovation.

scholarly journals Power-law behavior in millennium climate simulations

2012 ◽  
Vol 3 (1) ◽  
pp. 391-416
Author(s):  
S. V. Henriksson ◽  
P. Räisänen ◽  
J. Silen ◽  
H. Järvinen ◽  
A. Laaksonen
Keyword(s):  
Power Law ◽  
El Niño ◽  
El Nino ◽  
Temperature Record ◽  
Frequency Range ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Starting Point ◽  
The Impact ◽  
Global Mean

Abstract. Using a method of discrete Fourier transform with varying starting point and length of time window and the long time series provided by millennium Earth System Model simulations, we get good fits to power laws between two characteristic oscillatory timescales of the model climate: multidecadal (50–80 yr) and El Nino (3–6 yr) timescales. For global mean temperature, we fit β ~ 0.35 in a relation S(f) ~ f−β in a simulation without external climate forcing and β over 0.7 in a simulation with external forcing included. We also fit a power law with β ~ 8 to the narrow frequency range between El Nino frequencies and the Nyquist frequency. Regional variability in best-fit β is explored and the impact of choosing the frequency range on the result is illustrated. When all resolved frequencies are used, land areas seem to have lower βs than ocean areas on average, but when fits are restricted to frequencies below 1/(6 yr), this difference disappears, while regional differences still remain. Results compare well with measurements both for global mean temperature and for the Central England temperature record.

scholarly journals Exploring interaction effects from mechanisms between climate and land-use changes and the projected consequences on biodiversity

2021 ◽  
Vol 30 (12) ◽  
pp. 3685-3696
Author(s):  
Sarahi Nunez ◽  
Rob Alkemade
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Temperature Increase ◽  
Meta Analysis ◽  
Interaction Effects ◽  
Climate Change Effects ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Global Mean

AbstractChanges in climate and land use are major drivers of biodiversity loss. These drivers likely interact and their mutual effects alter biodiversity. These interaction mechanisms are rarely considered in biodiversity assessments, as only the combined individual effects are reported. In this study, we explored interaction effects from mechanisms that potentially affect biodiversity under climate change. These mechanisms entail that climate-change effects on, for example, species abundance and species’ range shifts depend on land-use change. Similarly, land-use change impacts are contingent on climate change. We explored interaction effects from four mechanisms and projected their consequences on biodiversity. These interactions arise if species adapted to modified landscapes (e.g. cropland) differ in their sensitivity to climate change from species adapted to natural landscapes. We verified these interaction effects by performing a systematic literature review and meta-analysis of 42 bioclimatic studies (with different increases in global mean temperature) on species distributions in landscapes with varying cropland levels. We used the Fraction of Remaining Species as the effect-size metric in this meta-analysis. The influence of global mean temperature increase on FRS did not significantly change with different cropland levels. This finding excluded interaction effects between climate and landscapes that are modified by other land uses than cropping. Although we only assessed coarse climate and land-use patterns, global mean temperature increase was a good, significant model predictor for biodiversity decline. This emphasizes the need to analyse interactions between land-use and climate-change effects on biodiversity simultaneously in other modified landscapes. Such analyses should also integrate other conditions, such as spatial location, adaptive capacity and time lags. Understanding all these interaction mechanisms and other conditions will help to better project future biodiversity trends and to develop coping strategies for biodiversity conservation.

scholarly journals Uncertainties in the global temperature change caused by carbon release from permafrost thawing

2012 ◽  
Vol 6 (2) ◽  
pp. 1367-1404 ◽  
Author(s):  
E. J. Burke ◽  
I. P. Hartley ◽  
C. D. Jones
Keyword(s):  
Soil Carbon ◽  
Climate Model ◽  
Mitigation Measures ◽  
High Concentration ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Carbon Release ◽  
The Impact ◽  
Global Mean

Abstract. Under climate change thawing permafrost will cause old carbon which is currently frozen and inert to become vulnerable to decomposition and release into the climate system. This paper develops a simple framework for estimating the impact of this permafrost carbon release on the global mean temperature (P-GMT). The analysis is based on simulations made with the Hadley Centre climate model (HadGEM2-ES) for a range of representative CO2 concentration pathways. Results using the high concentration pathway (RCP 8.5) suggest that by 2100 the annual methane (CH4) emission rate is 2–59 Tg CH4 yr−1 and 50–270 Pg C has been released as CO2 with an associated P-GMT of 0.08–0.36 °C (all 5th–95th percentile ranges). P-GMT is considerably lower – between 0.02 and 0.11 °C – for the low concentration pathway (RCP2.6). The uncertainty in climate model scenario causes about 50% of the spread in P-GMT by the end of the 21st century, indicating that the effect of permafrost thaw on global mean temperature is currently controllable by mitigation measures. The distribution of soil carbon, in particular how it varies with depth, contributes to about half of the remaining spread in P-GMT by 2100 with quality of soil carbon and decomposition processes contributing a further quarter each. These latter uncertainties could be reduced through additional observations. Over the next 20–30 yr, whilst scenario uncertainty is small, improving our knowledge of the quality of soil carbon will contribute significantly to reducing the spread in the, albeit relatively small, P-GMT.

scholarly journals The full greenhouse gases budget of Africa: synthesis, uncertainties and vulnerabilities

2013 ◽  
Vol 10 (5) ◽  
pp. 8343-8413 ◽  
Author(s):  
R. Valentini ◽  
A. Arneth ◽  
A. Bombelli ◽  
S. Castaldi ◽  
R. Cazzolla Gatti ◽  
...  
Keyword(s):  
Land Use ◽  
Carbon Emissions ◽  
Central Africa ◽  
Selective Logging ◽  
Co2 Uptake ◽  
Average Value ◽  
Reversible Loss ◽  
Ch4 And N2o ◽  
Carbon Losses ◽  
The Impact

Abstract. This paper, developed under the framework of the RECCAP initiative, aims at providing improved estimates of the carbon and GHG (CO2, CH4 and N2O) balance of continental Africa. The various components and processes of the African carbon and GHG budget were considered, and new and available data derived by different methodologies (based on inventories, ecosystem fluxes, models, and atmospheric inversions) were integrated. The related uncertainties were quantified and current gaps and weakness in knowledge and in the monitoring systems were also considered in order to provide indications on the future requirements. The vast majority of the results seem to agree that Africa is probably a small sink of carbon on an annual scale, with an average value of −0.61 ± 0.58 Pg C yr−1. Nevertheless the emissions of CH4 and N2O may turn Africa into a source in terms of CO2 equivalents. At sub-regional level there is a significant spatial variability in both sources and sinks, mainly due to the biome's differences and the different anthropic impacts, with southern Africa as the main source and central Africa, with its evergreen tropical forests, as the main sink. Emissions from land use change in Africa are significant (around 0.32 ± 0.05 Pg C yr−1) and even higher than the fossil fuel ones; this is a unique feature among all the continents. In addition there can be significant carbon losses from land even without changes in the land use (forest), as results from the impact of selective logging. Fires also play a significant role, with 1.03 ± 0.22 Pg C yr−1 of carbon emissions, mainly (90%) originated by savanna and woodland burning. But whether fire carbon emissions are compensated by CO2 uptake during the growing season, or are a non-reversible loss of CO2, remains unclear. Most of these figures are subjected to a significant interannual variability, on the order of ± 0.5 Pg C yr−1 in standard deviation, accounting for around 25% of the year-to-year variation in the global carbon budget. These results, even if still highly uncertain, show the important role that Africa plays in the carbon cycle at global level, both in terms of absolute values and variability.

Overshooting warming targets – temperature reversibility and implications for impacts, adaptation needs and near-term mitigation

2021 ◽  
Author(s):  
Carl-Friedrich Schleussner ◽  
Quentin Lejeune ◽  
Philippe Ciais ◽  
Thomas Gasser ◽  
Joeri Rogelj ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Global Warming ◽  
Large Scale ◽  
Carbon Dioxide Removal ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Removal Technologies ◽  
Near Term ◽  
The Impact ◽  
Global Mean

<p>Limiting global mean temperature increase to politically agreed temperature limits such as the 1.5°C threshold in the Paris Agreement becomes increasingly challenging. This has given rise to a class of overshoot emissions pathways in the mitigation literature that limit warming to such thresholds only after allowing for a temporary overshoot. However, substantial biogeophysical uncertainties remain regarding the large-scale deployment of Carbon Dioxide Removal technologies required to potentially reverse global warming. Additionally, beyond global mean temperature very little is known about the benefits of declining temperatures on impacts and adaptation needs. Here we will provide an overview of the current state of understanding regarding the reversibility of global warming, as well as impacts and adaptation needs under overshoot pathways.</p><p>We highlight the characteristics of the overshoot scenarios from the literature, and especially those that are compatible with identified sustainability limits for Carbon Dioxide Removal deployment. We will compare those characteristics with uncertainties arising from the Earth System’s response which may complicate the efforts to achieve a decrease in Global Mean Temperature after peak warming is reached. This part will include latest results of the permafrost carbon feedback under stylized overshoot scenarios. Eventually, we will summarise the state-of-the-art knowledge and present new results regarding the impacts of overshoot scenarios for non-linear and time-lagged responses such as sea-level rise, permafrost and glaciers. This will allow for a preliminary assessment of the impact and adaptation benefits of early mitigation compatible with a no or low overshoot pathways.</p>

scholarly journals A Stochastic Analysis of the Impact of Small-Scale Fluctuations on the Tropospheric Temperature Response to CO2 Doubling

2010 ◽  
Vol 23 (9) ◽  
pp. 2307-2319 ◽  
Author(s):  
Rita Seiffert ◽  
Jin-Song von Storch
Keyword(s):  
Climate Models ◽  
Climate Model ◽  
Small Scale ◽  
Tropospheric Temperature ◽  
Climate Response ◽  
Restoring Force ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
The Impact ◽  
Global Mean

Abstract The climate response to increased CO2 concentration is generally studied using climate models that have finite spatial and temporal resolutions. Different parameterizations of the effect of unresolved processes can result in different representations of small-scale fluctuations in the climate model. The representation of small-scale fluctuations can, on the other hand, affect the modeled climate response. In this study the mechanisms by which enhanced small-scale fluctuations alter the climate response to CO2 doubling are investigated. Climate experiments with preindustrial and doubled CO2 concentrations obtained from a comprehensive climate model [ECHAM5/Max Planck Institute Ocean Model (MPI-OM)] are analyzed both with and without enhanced small-scale fluctuations. By applying a stochastic model to the experimental results, two different mechanisms are found. First, the small-scale fluctuations can change the statistical behavior of the global mean temperature as measured by its statistical damping. The statistical damping acts as a restoring force that determines, according to the fluctuation–dissipation theory, the amplitude of the climate response to a change in external forcing (here, CO2 doubling). Second, the small-scale fluctuations can affect processes that occur only in response to the CO2 increase, thereby altering the change of the effective forcing on the global mean temperature.

scholarly journals Sea-spray geoengineering in the HadGEM2-ES earth-system model: radiative impact and climate response

2012 ◽  
Vol 12 (22) ◽  
pp. 10887-10898 ◽  
Author(s):  
A. Jones ◽  
J. M. Haywood
Keyword(s):  
Direct Effect ◽  
Indirect Effects ◽  
Earth System Model ◽  
System Model ◽  
Sea Spray ◽  
Earth System ◽  
Global Mean Temperature ◽  
Radiative Impact ◽  
The Impact ◽  
Global Mean

Abstract. The radiative impact and climate effects of geoengineering using sea-spray aerosols have been investigated in the HadGEM2-ES Earth system model using a fully prognostic treatment of the sea-spray aerosols and also including their direct radiative effect. Two different emission patterns were considered, one to maximise the direct effect in clear skies, the other to maximise the indirect effects of the sea-spray on low clouds; in both cases the emissions were limited to 10% of the ocean area. While the direct effect was found to be significant, the indirect effects on clouds were much more effective in reducing global mean temperature as well as having less of an impact on global mean precipitation per unit temperature reduction. The impact on the distribution of precipitation was found to be similar in character, but less in degree, to that simulated by a previous study using a much simpler treatment of this geoengineering process.

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