“…F-gases , Gernaat et al 2015. Third, although models tend to agree on the importance of aerosol forcing, uncertainty in the magnitude of aerosol forcing (Myhre et al 2013) and the lack of significant abatement from aerosol sources other than SO 2 (such as black carbon) deserves greater scrutiny within integrated assessment models, particularly given the attention to black carbon mitigation as a potential policy measure (Shindell et al 2012, Smith and Mizrahi 2013, Shindell et al 2017.…”
Section: Discussionmentioning
confidence: 99%
“…For this reason, recent studies have considered the role of non-CO 2 emissions explicitly. Some have focused on short-lived climate forcers, such as black carbon (BC) and methane, that have a warming effect (Shindell et al 2012, Bond et al 2013, Bowerman et al 2013, Smith and Mizrahi 2013, Shindell et al 2017, Stjern et al 2017, while others have focused on aerosols that have a net cooling effect (Gillett and Salzen 2013, Baker et al 2015, Hienola et al 2018, Samset et al 2018. Other studies have considered a wider array of non-CO 2 forcers (greenhouse gases (GHGs) and aerosols) in various ways (Meinshausen et al 2009, Rogelj et al 2015, Rogelj et al 2016, Matthews et al 2017, Millar et al 2017, Mengis et al 2018, Tokarska and Gillett 2018, Tokarska et al 2018.…”
The approximate proportional relationship between cumulative carbon emissions and instantaneous global temperature rise (the carbon budget approximation) has proven to be a useful concept to translate policy-relevant temperature objectives into CO 2 emissions pathways. However, when non-CO 2 forcing is changing along with CO 2 forcing, errors in the approximation increases. Using the GCAM model to produce an ensemble of ∼3000 scenarios, we show that linked changes in CO 2 forcing, aerosol forcing, and non-CO 2 greenhouse gas (GHG) forcing lead to an increase in total non-CO 2 forcing over the 21st century across mitigation scenarios. This increase causes the relationship between instantaneous temperature and cumulative CO 2 emissions to become more complex than the proportional approximation often assumed, particularly for low temperature objectives such as 1.5°C. The same linked changes in emissions also contribute to a near-term increase in aerosol forcing that effectively places a limit on how low peak temperature could be constrained through GHG mitigation alone. In particular, we find that 23% of scenarios that include CCS (but only 1% of scenarios that do not include CCS) achieve a temperature objective of 1.5°C without temperature overshoot.
“…F-gases , Gernaat et al 2015. Third, although models tend to agree on the importance of aerosol forcing, uncertainty in the magnitude of aerosol forcing (Myhre et al 2013) and the lack of significant abatement from aerosol sources other than SO 2 (such as black carbon) deserves greater scrutiny within integrated assessment models, particularly given the attention to black carbon mitigation as a potential policy measure (Shindell et al 2012, Smith and Mizrahi 2013, Shindell et al 2017.…”
Section: Discussionmentioning
confidence: 99%
“…For this reason, recent studies have considered the role of non-CO 2 emissions explicitly. Some have focused on short-lived climate forcers, such as black carbon (BC) and methane, that have a warming effect (Shindell et al 2012, Bond et al 2013, Bowerman et al 2013, Smith and Mizrahi 2013, Shindell et al 2017, Stjern et al 2017, while others have focused on aerosols that have a net cooling effect (Gillett and Salzen 2013, Baker et al 2015, Hienola et al 2018, Samset et al 2018. Other studies have considered a wider array of non-CO 2 forcers (greenhouse gases (GHGs) and aerosols) in various ways (Meinshausen et al 2009, Rogelj et al 2015, Rogelj et al 2016, Matthews et al 2017, Millar et al 2017, Mengis et al 2018, Tokarska and Gillett 2018, Tokarska et al 2018.…”
The approximate proportional relationship between cumulative carbon emissions and instantaneous global temperature rise (the carbon budget approximation) has proven to be a useful concept to translate policy-relevant temperature objectives into CO 2 emissions pathways. However, when non-CO 2 forcing is changing along with CO 2 forcing, errors in the approximation increases. Using the GCAM model to produce an ensemble of ∼3000 scenarios, we show that linked changes in CO 2 forcing, aerosol forcing, and non-CO 2 greenhouse gas (GHG) forcing lead to an increase in total non-CO 2 forcing over the 21st century across mitigation scenarios. This increase causes the relationship between instantaneous temperature and cumulative CO 2 emissions to become more complex than the proportional approximation often assumed, particularly for low temperature objectives such as 1.5°C. The same linked changes in emissions also contribute to a near-term increase in aerosol forcing that effectively places a limit on how low peak temperature could be constrained through GHG mitigation alone. In particular, we find that 23% of scenarios that include CCS (but only 1% of scenarios that do not include CCS) achieve a temperature objective of 1.5°C without temperature overshoot.
“…Environment change is likely to have various impacts on human health. Environment change has been positively related to human influences (IPCC, 2014;Shindell et al, 2017). A very important factor is rapid human population growth, which has been accompanied by enormous economic development and increasing sources of pollution such as vehicles and polluting industries.…”
Section: Controlling Human Population Growthmentioning
“…Mitigating climate change is multifaceted and there are several viable options available for cleaner energy (Inui et al, 1998; Shindell et al, 2017). Solar and wind energy production, for example, has increased significantly in recent years, but still suffers from fundamental engineering limitations; the two main ones being storage and transport.…”
Developing a laboratory scale or pilot scale chemical process into industrial scale is not trivial. The direct conversion of CO2 to methanol, and concomitant production of hydrogen from water electrolysis on large scale, are no exception. However, when successful, there are certain benefits to this process over the conventional process for producing methanol, both economic and environmental. In this article, we highlight some aspects that are unique to the process of converting pure CO2 to methanol. Starting from pure CO2 and a separate pure source of H2, rather than a mixture of CO, CO2, and H2 as is the case with syngas, simplifies the chemistry, and therefore also changes the reaction and purification processes from conventional methanol producing industrial plants. At the core of the advantages is that the reaction impurities are essentially limited to only water and dissolved CO2 in the crude methanol. In this paper we focus on several aspects of the process that direct conversion of CO2 to methanol enjoys over existing methods from conventional syngas. In particular, we discuss processes for removing CO2 from a methanol synthesis intermediate product stream by way of a stripper unit in an overhead stream of a distillation column, as well as aspects of a split tower design for the distillation column with an integrated vapo-condenser and optionally also featuring mechanical vapor re-compression. Lastly, we highlight some differences in reactor design for the present system over those used in conventional plants.
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