There are two main sources of greenhouse gas emissions: stationary (e.g., power plants, refineries) and mobile (e.g., cars, trucks). Transportation contributes 24% of energy-related CO2 emissions, with fossil fuels dominating. LNG in maritime transport shows potential for reduced CO2 emissions, but methane leakages must be addressed. Coal has the highest CO2 emissions factor among widely used fuels.
Approximately 91% of transportation energy globally comes from petroleum fuels, creating 29% of US and 20% of global greenhouse gas emissions. Biofuels offer potential emission reductions but raise land use concerns. Ethanol’s carbon emissions have decreased, and ongoing research aims to further reduce them. Government support and investments are driving biofuel expansion.
Many experts advocate for “putting a price on carbon” to reduce greenhouse gas emissions and address climate change. This involves capturing the external costs of emissions and linking them to their sources through a price. Approaches include emissions trading systems (e.g., “cap and trade”) and carbon taxes. Currently, 73 initiatives cover 23% of global emissions, with examples in South Africa and the European Union.
Stock market indices reflect market performance and health. Carbon indices, like the S&P 500 Carbon Efficient Index (CEI), weigh companies based on carbon emissions per revenue unit, aiming for lower carbon exposure without altering industry allocations. Over 5 years, the CEI boasted a robust 13% return, outperforming many major indices.
Major financial institutions’ practices are not climate-friendly, with policies disconnecting short-term targets from required long-term climate actions. A Columbia University report highlights financial institutions’ political influence, using lobbying and campaign contributions, often obstructing climate policy. The report suggests measures for shifting towards positive climate action.
Climate justice recognizes the responsibility of the wealthy for climate change, which disproportionately impacts the vulnerable. Urban climate action plans are increasingly addressing justice, but some cities still lack such plans. Larger cities tend to prioritize justice more, and sectors like energy efficiency and clean energy receive greater attention. More efforts are needed to achieve just and inclusive urban climate transitions.
Cryptocurrencies like Bitcoin rely on blockchain technology and crypto mining, which consume massive amounts of electricity and have significant carbon footprints. The lack of transparency and regulation in the industry raises concerns about the economic, social, and environmental costs associated with crypto mines.
Direct Air Capture and Storage (DACCS) systems, which remove CO2 from the atmosphere, offer a significant carbon benefit depending on the energy mix of the regional grid. The greatest carbon benefit is achieved when DAC processes utilize zero-carbon sources like renewables and nuclear power. The ongoing decarbonization of the grid in most regions of the United States supports the effectiveness of DAC and electrification technologies.
Methane emissions from coal mines are a significant concern for greenhouse gas reduction. Certain mines, known as “superemitters,” contribute a large proportion of global methane emissions. Factors like mine depth and coal rank affect methane content. While reducing coal use in electricity generation is important, mitigating methane emissions from mines needs greater attention.
