Comparative Effectiveness of Carbon Pricing, Industrial Subsidies, and Innovation Support in Green New Deal Strategies: A Systematic Literature Review

The accelerating climate emergency has prompted governments worldwide to adopt comprehensive Green New Deal strategies that combine multiple policy instruments to deliver deep decarbonization while sustaining economic growth. This study conducts a systematic literature review, structured around the PRISMA 2020 protocol, of three core policy instruments central to Green New Deal frameworks: carbon pricing, industrial subsidies including feed in tariffs, and public innovation support. Drawing on 147 quantitative studies published between 1990 and 2025 and indexed in Web of Science, Scopus, and EconLit, we standardize effect sizes using semi elasticity coefficients, abatement cost in dollars per ton of carbon dioxide, and patent based innovation indicators. Results show that carbon pricing achieves the lowest unit abatement cost in the short to medium term, with semi elasticities clustered between 0.003 and 0.008 per dollar per ton increase and minimal macroeconomic disruption. Industrial subsidies and feed in tariffs accelerate technology deployment and trigger learning by doing cost reductions of roughly 20 percent per doubling of cumulative capacity, although early stage abatement costs frequently exceed 100 dollars per ton. Public innovation support increases high quality clean technology patents by 10 to 20 percent but exhibits long temporal lags. The three instruments are complementary rather than substitutable, and an optimally sequenced combination dominates any single instrument approach. The review provides a quantitative evidence base to support the design of effective Green New Deal policy packages.