The Unassuming Economist

From the US Department of Energy:

” This report reviews scientific certainties and uncertainties in how anthropogenic carbon dioxide (CO2) and other greenhouse gas emissions have affected, or will affect, the Nation’s climate, extreme weather events, and selected metrics of societal well-being. Those emissions are increasing the concentration of CO2 in the atmosphere through a complex and variable carbon cycle, where some portion of the additional CO2 persists in the atmosphere for centuries.

Elevated concentrations of CO2 directly enhance plant growth, globally contributing to “greening” the planet and increasing agricultural productivity [Section 2.1, Chapter 9]. They also make the oceans less alkaline (lower the pH). That is possibly detrimental to coral reefs, although the recent rebound of the Great Barrier Reef suggests otherwise [Section 2.2].

Carbon dioxide also acts as a greenhouse gas, exerting a warming influence on climate and weather [Section 3.1]. Climate change projections require scenarios of future emissions. There is evidence that scenarios widely-used in the impacts literature have overstated observed and likely future emission trends [Section 3.1].

The world’s several dozen global climate models offer little guidance on how much the climate responds to elevated CO2, with the average surface warming under a doubling of the CO2 concentration ranging from 1.8°C to 5.7°C [Section 4.2]. Data-driven methods yield a lower and narrower range [Section 4.3]. Global climate models generally run “hot” in their description of the climate of the past few decades − too much warming at the surface and too much amplification of warming in the lower- and mid-troposphere [Sections 5.2-5.4]. The combination of overly sensitive models and implausible extreme scenarios for future emissions yields exaggerated projections of future warming.

Most extreme weather events in the U.S. do not show long-term trends. Claims of increased frequency or intensity of hurricanes, tornadoes, floods, and droughts are not supported by U.S. historical data [Sections 6.1-6.7]. Additionally, forest management practices are often overlooked in assessing changes in wildfire activity [Section 6.8]. Global sea level has risen approximately 8 inches since 1900, but there are significant regional variations driven primarily by local land subsidence; U.S. tide gauge measurements in aggregate show no obvious acceleration in sea level rise beyond the historical average rate [Chapter 7].

Attribution of climate change or extreme weather events to human CO2 emissions is challenged by natural climate variability, data limitations, and inherent model deficiencies [Chapter 8]. Moreover, solar activity’s contribution to the late 20th century warming might be underestimated [Section 8.3.1].

Both models and experience suggest that CO2-induced warming might be less damaging economically than commonly believed, and excessively aggressive mitigation policies could prove more detrimental than beneficial [Chapters 9, 10, Section 11.1]. Social Cost of Carbon estimates, which attempt to quantify the economic damage of CO2 emissions, are highly sensitive to their underlying assumptions and so provide limited independent information [Section 11.2].

U.S. policy actions are expected to have undetectably small direct impacts on the global climate and any effects will emerge only with long delays [Chapter 12].”

From a paper by Heru Wahyudi, Sabila Ramadani, and Ukhti Ciptawaty:

“Human welfare can decrease as a result of a polluted environment. This study aims to examine the relevance of the Environmental Kuznets Curve (EKC) theory in OPEC member countries; besides that, this study also wants to see the effect of GDP per capita and fossil energy consumption on carbon dioxide gas emissions in OPEC countries. Method: this research is included in the descriptive quantitative method using the panel data regression method. The data used in the 2005-2020 period comes from the World Bank and Our World. Namely the GDP per capita variable, the carbon dioxide emission variable and fossil energy consumption. The results obtained from this study are that the hypothesis in EKC theory is relevant or occurs in OPEC member countries. In addition, per capita GDP and fossil energy consumption also positively affected OPEC member countries for the 2005-2020 period. It means that an increase in the economy will cause environmental damage by increasing the concentration of carbon dioxide gas emissions due to the use of fossil energy. However, at some point, a high economy will reduce environmental damage due to an economic orientation that focuses on the environment so that it uses environmentally friendly energy.”

From a paper by Charlotte Liotta and Jeroen van den Bergh:

“The long-standing growth-versus-environment debate has centered on national and global scales, devoting little attention to cities despite steadily increasing urban concentrations of population, activities and emissions. This Perspective clarifies how this debate plays out for cities by relating four urban growth dimensions—economic, population, spatial and environmental—to the narratives of green growth, degrowth and post-growth. To this end, we review theoretical and empirical insights about links between growth dimensions. Specific issues addressed include horizontal spillovers among cities, vertical policy integration and local experiments. Thus we connect the abstract growth-versus-environment debate to evidence regarding urban environmental policy.”

From a paper by Boyang Lia, Runze Chena, and Yuqin Dua:

“The power generation mix in China heavily relies on fossil energy sources, impeding
the advancement of clean power generation and emission reduction efforts. This paper
presents a macroeconomic model incorporating Emissions Trading Systems (ETS),
clean energy subsidies, and intertemporal learning behavior. It examines how carbon
pricing and clean subsidy policies influence the power generation sector and emission
reduction goals. The findings indicate that (1) pricing strategies based on total
emissions effectively drive emission reductions but may not adequately incentivize
cleaner energy transitions. (2) Increasing clean energy subsidies encourages a shift
towards cleaner technologies, although the impact on emission reductions is moderate.
(3) Combining both policies proves to be more effective than implementing either one
alone. (4) There exists a gap in understanding the clean power generation industry, with
both policies contributing to knowledge accumulation in this sector. The insights from
this study are valuable for countries employing ETS mechanisms.”

From a paper by Muhammad Ibrahim Shah, Matteo Foglia, Umer Shahzad, and Zeeshan Fareed:

“This paper investigates how oil price, COVID-19, and global energy innovation can affect carbon emissions under time- and frequency-varying perspectives. We contribute to the literature by being the first research to document the relationship between these variables in the short and long run (dynamically) at different frequencies in a multivariate context, thus providing a more detailed picture of the forces driving CO₂ emissions. For this purpose, we use a novel methodology, i.e., the wavelet local multiple correlation (WLMC) recently developed by Polanco-Martínez et al. (2020). The results provide fresh evidence of long-run asymmetric dynamic correlations, highlighting how the oil price plays a key role in the dynamics of CO₂ emissions. Moreover, we find that, during the long period, there is a strong negative co-movement between CO₂ and the global energy innovation index, i.e., more investment in clean energy induces less emission. Supported by our findings, this research suggests crucial policy implications and insights for the governments worldwide in their efforts to revive their economies amidst the pandemic and environmental uncertainties.”