Comprehensive evidence implies a higher social cost of CO2.

The social cost of carbon dioxide (SC-CO2) measures the monetized value of the damages to society caused by an incremental metric tonne of CO2 emissions and is a key metric informing climate policy. Used by governments and other decision-makers in benefit-cost analysis for over a decade, SC-CO2 estimates draw on climate science, economics, demography and other disciplines. However, a 2017 report by the US National Academies of Sciences, Engineering, and Medicine1 (NASEM) highlighted that current SC-CO2 estimates no longer reflect the latest research. The report provided a series of recommendations for improving the scientific basis, transparency and uncertainty characterization of SC-CO2 estimates. Here we show that improved probabilistic socioeconomic projections, climate models, damage functions, and discounting methods that collectively reflect theoretically consistent valuation of risk, substantially increase estimates of the SC-CO2. Our preferred mean SC-CO2 estimate is $185 per tonne of CO2 ($44-$413 per tCO2: 5%-95% range, 2020 US dollars) at a near-term risk-free discount rate of 2%, a value 3.6 times higher than the US government's current value of $51 per tCO2. Our estimates incorporate updated scientific understanding throughout all components of SC-CO2 estimation in the new open-source Greenhouse Gas Impact Value Estimator (GIVE) model, in a manner fully responsive to the near-term NASEM recommendations. Our higher SC-CO2 values, compared with estimates currently used in policy evaluation, substantially increase the estimated benefits of greenhouse gas mitigation and thereby increase the expected net benefits of more stringent climate policies.

Estimating a social cost of carbon for global energy consumption.

Estimates of global economic damage caused by carbon dioxide (CO2) emissions can inform climate policy1-3. The social cost of carbon (SCC) quantifies these damages by characterizing how additional CO2 emissions today impact future economic outcomes through altering the climate4-6. Previous estimates have suggested that large, warming-driven increases in energy expenditures could dominate the SCC7,8, but they rely on models9-11 that are spatially coarse and not tightly linked to data2,3,6,7,12,13. Here we show that the release of one ton of CO2 today is projected to reduce total future energy expenditures, with most estimates valued between -US$3 and -US$1, depending on discount rates. Our results are based on an architecture that integrates global data, econometrics and climate science to estimate local damages worldwide. Notably, we project that emerging economies in the tropics will dramatically increase electricity consumption owing to warming, which requires critical infrastructure planning. However, heating reductions in colder countries offset this increase globally. We estimate that 2099 annual global electricity consumption increases by about 4.5 exajoules (7 per cent of current global consumption) per one-degree-Celsius increase in global mean surface temperature (GMST), whereas direct consumption of other fuels declines by about 11.3 exajoules (7 per cent of current global consumption) per one-degree-Celsius increase in GMST. Our finding of net savings contradicts previous research7,8, because global data indicate that many populations will remain too poor for most of the twenty-first century to substantially increase energy consumption in response to warming. Importantly, damage estimates would differ if poorer populations were given greater weight14.

The mortality cost of carbon.

Many studies project that climate change can cause a significant number of excess deaths. Yet, in integrated assessment models (IAMs) that determine the social cost of carbon (SCC) and prescribe optimal climate policy, human mortality impacts are limited and not updated to the latest scientific understanding. This study extends the DICE-2016 IAM to explicitly include temperature-related mortality impacts by estimating a climate-mortality damage function. We introduce a metric, the mortality cost of carbon (MCC), that estimates the number of deaths caused by the emissions of one additional metric ton of CO2. In the baseline emissions scenario, the 2020 MCC is 2.26 × 10‒4 [low to high estimate -1.71× 10‒4 to 6.78 × 10‒4] excess deaths per metric ton of 2020 emissions. This implies that adding 4,434 metric tons of carbon dioxide in 2020-equivalent to the lifetime emissions of 3.5 average Americans-causes one excess death globally in expectation between 2020-2100. Incorporating mortality costs increases the 2020 SCC from $37 to $258 [-$69 to $545] per metric ton in the baseline emissions scenario. Optimal climate policy changes from gradual emissions reductions starting in 2050 to full decarbonization by 2050 when mortality is considered.

Near-real-time monitoring of global CO2 emissions reveals the effects of the COVID-19 pandemic.

The COVID-19 pandemic is impacting human activities, and in turn energy use and carbon dioxide (CO2) emissions. Here we present daily estimates of country-level CO2 emissions for different sectors based on near-real-time activity data. The key result is an abrupt 8.8% decrease in global CO2 emissions (-1551 Mt CO2) in the first half of 2020 compared to the same period in 2019. The magnitude of this decrease is larger than during previous economic downturns or World War II. The timing of emissions decreases corresponds to lockdown measures in each country. By July 1st, the pandemic's effects on global emissions diminished as lockdown restrictions relaxed and some economic activities restarted, especially in China and several European countries, but substantial differences persist between countries, with continuing emission declines in the U.S. where coronavirus cases are still increasing substantially.

Estimating the Impact of Carbon Dioxide Absorbent Performance Differences on Absorbent Cost During Low-Flow Anesthesia.

BACKGROUND: Reducing fresh gas flow when using a circle anesthesia circuit is the most effective strategy for reducing both inhaled anesthetic vapor cost and waste. As fresh gas flow is reduced, the amount of exhaled gas rebreathed increases, but the utilization of carbon dioxide absorbent increases as well. Reducing fresh gas flow may not make economic sense if the increased cost of absorbent utilization exceeds the reduced cost of anesthetic vapor. The primary objective of this study was to determine the minimum fresh gas flow at which absorbent costs do not exceed vapor savings. Another objective is to provide a qualitative insight into the factors that influence absorbent performance as fresh gas flow is reduced. METHODS: A mathematical model was developed to compare the vapor savings with the cost of carbon dioxide absorbent as a function of fresh gas flow. Parameters of the model include patient size, unit cost of vapor and carbon dioxide absorbent, and absorbent capacity and efficiency. Boundaries for fresh gas flow were based on oxygen consumption or a closed-circuit condition at the low end and minute ventilation to approximate an open-circuit condition at the high end. Carbon dioxide production was estimated from oxygen consumption assuming a respiratory quotient of 0.8. RESULTS: For desflurane, the cost of carbon dioxide absorbent did not exceed vapor savings until fresh gas flow was almost equal to closed-circuit conditions. For sevoflurane, as fresh gas flow is reduced, absorbent costs increase more slowly than vapor costs decrease so that total costs are still minimized for a closed circuit. Due to the low cost of isoflurane, even with the most effective absorbent, the rate of absorbent costs increase more rapidly than vapor savings as fresh gas flow is reduced, so that an open circuit is least expensive. The total cost of vapor and absorbent is still lowest for isoflurane when compared with the other agents. CONCLUSIONS: The relative costs of anesthetic vapor and carbon dioxide absorbent as fresh gas flow is reduced are dependent on choice of anesthetic vapor and performance of the carbon dioxide absorbent. Absorbent performance is determined by the product selected and strategy for replacement. Clinicians can maximize the performance of absorbents by replacing them based on the appearance of inspired carbon dioxide rather than the indicator. Even though absorbent costs exceed vapor savings as fresh gas flow is reduced, isoflurane is still the lowest cost choice for the environmentally sound practice of closed-circuit anesthesia.

The role of ICT and financial development in CO2 emissions and economic growth.

This study explores the role of the information and communication technology (ICT) and financial development (FD) in both carbon emissions and economic growth for the G7 countries for the period 1990 to 2014. Using PMG, we found that the ICT has a long-run positive effect on emissions, while FD is a weak determinant. The interactive term between the ICT and FD produces negative coefficients. Also, both the variables are found to impact negatively on economic growth. However, their interaction shows that they have mixed effect on economic growth, i.e., positive in the short run and negative in the long run. Policy implications were designed based on these results.

The technological and economic prospects for CO2 utilization and removal.

The capture and use of carbon dioxide to create valuable products might lower the net costs of reducing emissions or removing carbon dioxide from the atmosphere. Here we review ten pathways for the utilization of carbon dioxide. Pathways that involve chemicals, fuels and microalgae might reduce emissions of carbon dioxide but have limited potential for its removal, whereas pathways that involve construction materials can both utilize and remove carbon dioxide. Land-based pathways can increase agricultural output and remove carbon dioxide. Our assessment suggests that each pathway could scale to over 0.5 gigatonnes of carbon dioxide utilization annually. However, barriers to implementation remain substantial and resource constraints prevent the simultaneous deployment of all pathways.

Is Carbon Dioxide (CO2) Emission an Important Factor Affecting Healthcare Expenditure? Evidence from China, 2005-2016.

As a result of China's economic growth, air pollution, including carbon dioxide (CO2) emission, has caused serious health problems and accompanying heavy economic burdens on healthcare. Therefore, the effect of carbon dioxide emission on healthcare expenditure (HCE) has attracted the interest of many researchers, most of which have adopted traditional empirical methods, such as ordinary least squares (OLS) or quantile regression (QR), to analyze the issue. This paper, however, attempts to introduce Bayesian quantile regression (BQR) to discuss the relationship between carbon dioxide emission and HCE, based on the longitudinal data of 30 provinces in China (2005-2016). It was found that carbon dioxide emission is, indeed, an important factor affecting healthcare expenditure in China, although its influence is not as great as the income variable. It was also revealed that the effect of carbon dioxide emission on HCE at a higher quantile was much smaller, which indicates that most people are not paying sufficient attention to the correlation between air pollution and healthcare. This study also proves the applicability of Bayesian quantile regression and its ability to offer more valuable information, as compared to traditional empirical tools, thus expanding and deepening research capabilities on the topic.

The causal nexus between energy consumption, carbon emissions and economic growth: New evidence from China, India and G7 countries using convergent cross mapping.

Understanding the causality between energy consumption, carbon emissions and economic growth is helpful for policymakers to formulate energy, environmental and economic policies. For the first time, based on nonlinear dynamics, this paper employs multispatial convergent cross mapping (CCM) to revisit the energy-carbon-economy causation for China, India and the G7 countries using both aggregate data and per capita data. The findings indicate that there are significant differences between developing countries and developed countries. A bidirectional nexus between energy consumption, carbon emissions and economic growth is found in China and India, but various causal relationships are identified in the G7 countries, including bidirectional, unidirectional and neutral nexus. The results confirm that the decoupling phenomenon is common in most G7 countries. By leveraging a variety of samples and a new approach, this study provides new evidence for policy authorities to formulate country-specific policies to obtain better environmental quality while achieving sustainable economic growth.

Environmental Kuznets Curve and Trade Openness in Turkey: Bootstrap ARDL Approach with a Structural Break.

In this study, the validity of the environmental Kuznets curve (EKC) hypothesis is examined with the newly developed bootstrap autoregressive distributed lag (ARDL) approach by incorporating the effects of trade openness for Turkey from 1969 to 2017. The bootstrap ARDL approach results show that there is a long-run relationship between per capita carbon dioxide (CO2) emissions, per capita real income, and trade openness in the presence of one structural break. The results of the long-run estimators indicate that the inverted U-shaped EKC hypothesis is valid, and trade openness has an increasing impact on CO2 emissions. However, Turkey has not yet reached the level of income necessary to reduce pollution. The results of the Fourier Toda-Yamamoto Granger causality test also show that unidirectional causality runs through per capita real income and trade openness to per capita CO2 emissions. In addition to these findings, it has been determined that the decrease in growth rate and production experienced during the 2001 financial crisis in Turkey reduced environmental pollution in both the short and long runs. Consequently, these results show that the scale and composition effects outweigh for economic growth and trade openness in Turkey.

Investigating the nexus among environmental pollution, economic growth, energy use, and foreign direct investment in 6 selected sub-Saharan African countries.

This research seeks to enhance the current literature by exploring the nexus among environmental contamination, economic growth, energy use, and foreign direct investment in 6 selected sub-Saharan African nations for a time of 34 years (1980-2014). By applying panel unit root (CADF and CIPS, cross-sectional independence test), panel cointegration (Pedroni and Kao cointegration test, panel PP, panel ADF), Hausman poolability test, and an auto-regressive distributed lag procedure in view of the pooled mean group estimation (ARDL/PMG), experimental findings disclose that alluding to the related probability values, the null hypothesis of cross-sectional independence for all variables is rejected because they are not stationary at levels but rather stationary at their first difference. The variables are altogether integrated at the same order I(1). Findings revealed that there is a confirmation of a bidirectional causality between energy use and CO2 in the short-run and one-way causality running from energy use to CO2 in the long run. There is additionally a significant positive outcome and unidirectional causality from CO2 to foreign direct investment in the long run yet no causal relationship in the short run. An increase in energy use by 1% causes an increase in CO2 by 49%. An increase in economic growth by 1% causes an increment in CO2 by 16% and an increase in economic growth squared by 1% diminishes CO2 by 46%. The positive and negative impacts of economic growth and its square approve the EKC theory. To guarantee sustainable economic development goal, more strict laws like sequestration ought to be worked out, use of sustainable power source ought to be stressed, and GDP ought to be multiplied to diminish CO2 by the utilization of eco-technology for instance carbon capturing, to save lives and also to maintain a green environment.

Green certification, e-commerce, and low-carbon economy for international tourist hotels.

Increasing population and over-consumption are placing unprecedented demands on agriculture and natural resources. The Earth is suffering from global warning and environmental destruction while our agricultural systems are concurrently degrading land, water, biodiversity, and climate on a global scale. For a sustainable future, green certification, e-commerce, and environment education can boost low-carbon economy with decreasing carbon emissions, but very few researches address them for the hotel industry. This research studies the performance impact of e-commerce, international hotel chain, local hotel chain, and green certification for carbon emission reductions of international tourist hotels of Taiwan. It reveals that, after a sufficiently long time, there is an improvement in the environmental and economic performance of the green-certified hotel group. In addition, it reveals that, as recommended by the operation policy, the international hotel chain group together with e-commerce has better performance than local hotel chain. It is also discussed how to sustain the continuing improvement in low-carbon performance of the hotel industry.

Carbon price volatility: The case of China.

Based on carbon spot prices selected from seven carbon pilots, we assess the financial performances related to carbon volatility in China on the overall perspective. According to the results, the Chinese carbon market fluctuated severely at the beginning of carbon trading, but has stabilised in general, despite several dramatic changes related to 'yearly compliance events'. Long-term memory exists in the volatility series. Moreover, asymmetry exists in the Chinese carbon market, and volatility reacts more severely to good news than to bad news. Finally, we discuss our empirical results, and make certain suggestions regarding firms' awareness, international cooperation and individual investors not only for policy makers in China but also for other developing countries who are contemplating either commencing carbon trading or improving the current market.