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Equivalence metrics used to quantify the relative climate impacts of different atmospheric forcers serve an essential function in policy and economic discussions about global climate change. The 100-year global warming potential (GWP-100), the most established greenhouse gas (GHG) equivalence metric, is used within the Kyoto Protocol, and in most emissions inventory, trading and offset mechanisms, to assign the mitigation value of non-carbon dioxide greenhouse gases relative to carbon dioxide. In recent literature the GWP-100 and alternative metrics have been used to compare various anthropogenic climate forcers with respect to a wide range of environmental and economic goals. Building on this work, we examine how 16 different static and time-varying CO 2 -equivalence schemes might influence GHG mitigation across sectors and gases in a perfect and fluid global mitigation regime. This mitigation regime is guided by achieving a global mean radiative forcing (RF) of 5.7 Wm −2 in 2100 from 1765 levels through a mitigation policy of prescribed emissions reductions in each decade. It was found that static metrics defined on 20-instead of 100-year time horizons favor mitigation strategies that maximize the abatement of short-lived gases (e.g. methane), on average resulting in an RF from methane in 2100 of 0.5 Wm −2 instead of 1.1 Wm −2 from 100-year metrics. Similarly, metrics that consider integrated rather than end-point climate impacts imply mitigation strategies that maximize mitigation of shorter-lived GHGs, resulting in higher abatement of agriculture and waste emissions. Comparing extreme scenarios, these mitigation shifts across gases and sectors result in a nearly 30% difference in the representation of methane in global cumulative emissions reductions. This shift across gases and sectors to mitigate shorter-lived GHGs, in lieu of longer-lived GHGs like carbon dioxide, has implications for the long-term warming commitment due to 21st century emissions.

Problem, Research Strategy, and Findings: The Low-Income Housing Tax Credit (LIHTC) is the most common financing mechanism for the production of subsidized housing in America. We investigate how and to what extent states are currently using LIHTC to prepare for and recover from disasters. We systematically code guidelines in the 2017 LIHTC qualified allocation plans from 53 states and territories to identify disaster-related provisions. Twenty-four states and territories include provisions for preparedness or recovery in their allocation plans, of which 13 include only preparedness provisions, three include only recovery provisions, and eight include both types. Preparedness provisions address project design and siting, whereas recovery provisions direct credits to disaster-affected areas or the replacement of damaged units. Using t-tests, we compare three sets of states-those without any disaster-related provisions, those with either preparedness or recovery provisions, and those with both types of provisions-across measures of housing cost, demographic composition, disaster exposure, and political ideology. States with higher homeownership rates, lower home values, and lower rents are more likely than other states to have either or both types of provisions. Future research should investigate why this trend is the case to better inform affordable housing policy. Takeaway for Practice: State governments could mitigate disaster-related hazards and help speed recovery by including locallyrelevant preparedness and recovery provisions in their LIHTC allocation plans. These provisions could incentivize resilient construction, weigh the social costs and benefits of LIHTC construction in floodplains, or waive program rules to address post-disaster housing shortages.