Climate breakdown is seriously harming our seas and ocean, making them warmer and more acidic, and depleting the water of oxygen. This impacts all marine life. Individuals and industries must quickly and steeply reduce their climate emissions if we are to avoid the worst effects of global heating. This includes the shipping industry, where emissions are large and growing fast. It also includes power generation, where the urgent shift to renewables must be managed to ensure that offshore wind farms and other types of marine renewable energy do not harm ocean life.