  The international community aims to limit global warming to 1.5{\deg}C, but
little progress has been made towards a global, cost-efficient, and fair
climate mitigation plan to deploy carbon dioxide removal (CDR) at the Paris
Agreement's scale. Here, we investigate how different CDR options - AR, BECCS,
and DACCS - might be deployed to meet the Paris Agreement's CDR objectives. We
find that international cooperation in climate mitigation policy is key for
deploying the most cost-efficient CDR pathway - comprised of BECCS, mainly
(74%), and AR (26%) -, allowing to take the most advantage of regional
bio-geophysical resources and socio-economic factors, and time variations, and
therefore minimising costs. Importantly, with international cooperation, the
spatio-temporal evolution of the CDR pathway differs greatly from the
socio-economically fair regional allocation of the Paris Agreement's CDR
objectives. With limited, or no international cooperation, we find that the
likelihood of delivering these CDR objectives decreases, as deploying CDR
pathways becomes significantly more challenging and costly - particularly when
leading to the deployment of DACCS. Moreover, we show that developing
international cooperation policy instruments - such as an international market
for negative emissions trading - can deliver, simultaneously, cost-efficient
and equitable CDR at the Paris Agreement's scale, by incentivising
participating nations to meet their share of the Paris Agreement's CDR
objectives, whilst making up for the uneven distribution of CDR potentials
across the world. Crucially, we conclude that international cooperation is
imperative, as soon as possible, to preserve the feasibility and sustainability
of future CDR pathways, and ensure that future generations do not bear the
burden, increasingly costlier, of climate mitigation inaction.
