The world’s oceans have been warming over the past few decades. While the warming signal is not straightforward, scientists have recently concluded that the observed warming is caused by human-induced climate change, and that natural forcing, such as by solar or volcanic factors, cannot explain the phenomenon.
- Barnett, Tim et al. “Penetration of Human-Induced Warming into the World’s Oceans.” Science. 309(5732): 284-287 (8 July 2005). Science Express on 2 June 2005 at www.sciencemag.org
The study demonstrates that modeling uncertainties are quite small – and preclude a simple “natural fluctuation” explanation for ocean warming. The authors thus conclude the warming is caused by human-induced climate forcing. In addition, the authors offer new confidence in climate models and suggest that global models can make reliable predictions for the next two to three decades.
Implications: Over the past decade, policymakers have called for only limited climate action based on the assumption that the science of climate change may be wrong. Those holding this view have claimed that uncertainties in the underlying physics mean that human induced changes in atmospheric composition would only lead to insignificant changes in the climate system. This study, which concludes with confidence that ocean warming is due to human-induced climate change (which is in turn caused by the release of greenhouse gas emissions), solidly refutes those skeptical views. Furthermore, the study’s conclusions that oceans are warming suggests that we can expect substantial additional impacts as the climate system moves into a new global temperature equilibrium.
