Aaron Matthius Eger, Adriana Verges, Chang Geun Choi, Hartvig Christie, Melinda A. Coleman, Camilla W. Fagerli, Daisuke Fujita, Masatoshi Hasegawa, Jeong Ha Kim, Mariana Mayer-Pinto

Kelps form extensive underwater forests that underpin valuable ecosystem goods and services in temperate and polar rocky coastlines worldwide. Stressors such as ocean warming and pollution are causing regional declines of kelp forests and their associated services worldwide. Kelp forest restoration is becoming a prominent management intervention, but we have little understanding of what drives restoration success at appropriate spatial scales. This is a fundamental issue because of the typical mismatch between the scale of degradation and the scale of the intervention of these systems. Restoration guidelines commonly discuss project elements such as defining goals and metrics of success, the removal or mitigation of relevant stressors and ecological knowledge of the species, but institutional and financial support that underpins all these requirements is rarely discussed or emphasized. We begin to address this gap and review the world’s largest scale kelp restoration projects, involving four countries and six kelp genera, initiated in response to different causes of decline. We argue that to restore kelp at scale, adequate financing and institutional support are critical to overcome ecological and environmental limitations. As kelp restoration efforts progress into a future of increasing climate change, this logistical support element is likely to become even more important as innovative approaches have higher costs.