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To contain global warming to between 2 C and 1.5 C, global greenhouse gas emissions must be cut 25 to 50 percent below 2019 levels by 2030. Even if fully achieved, current country pledges would cut global emissions by just 11 percent. This Note presents illustrative options for closing this ambition gap equitably and discusses their economic impacts across countries. Options exist to accelerate a global just transition in this decade, involving greater emission reductions by high-income countries and climate finance, but further delays in climate action would put 1.5 C beyond reach. Global abatement costs remain low under 2 C-consistent scenarios, with burdens rising with income levels. With efficient policies of carbon pricing with productive revenue use, welfare costs become negative when including domestic environmental co-benefits, before even counting climate benefits. GDP effects from global decarbonization remain uncertain, but modeling sug gests they exceed abatement costs especially for carbon-intensive and fossil-fuel-exporting countries. Ratcheting up climate finance can help make global decarbonization efforts more progressive.