Huge amounts of greenhouse gases lurk in the oceans, and could make warming far worse
There is plenty of evidence that in the past, during warm times there were major outgassing events. Not that the planet changed noticeably. What happens if we go from 0,00018% methane in the iar to 0,0018%. Nothing at all. The methane will be oxidized very quickly. Some might burn if there is an ignition source close to the vent. But there wont be warming. Its the sun that drives this.