Climate change will upend the 21^st century world order. It will redefine how we live and work, and change the systems of production, trade, economics, and finance. Even now, in the midst of a global pandemic, it is clear that climate change will be the defining issue of this century. In fact, COVID-19 has only underscored the inadequacy of our responses to global crises and heightened the urgency of this call to action. 21^st century diplomacy will have to raise climate ambition, shape the transformative systems change needed, and promote and facilitate new modes of multilateral collaboration.