Let me start this blog by quoting—verbatim—several key conclusions from the Intergovernmental Panel on Climate Change’s Climate Change 2013, also known as the IPCC’s Fifth Assessment Report (AR5):
Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia… The atmosphere and the ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased… Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850… Changes in many extreme weather and climate events have been observed since about 1950… It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century…
The IPCC does not mince words. And despite a frontal assault by climate skeptics, attempting to use the scientific nuances of the report to sow doubt, the conclusions stand as a rock. Some media outlets are emphasizing the small shifts in scientific understanding or the recent reduction in the rate of warming of the atmosphere (as opposed to oceans), leaving casual readers confused if indeed this is the most definitive assessment of the risks of human-caused warming. It is! The most rigorous scientific peer review process ever assembled by humankind is leaving no more room for doubt.
With a 95 percent certainty of the main conclusion that mankind’s emissions are the leading cause for continued climate change, the debate around the science is now truly settled. Yes of course, climate models will be fine-tuned further, and more research will shed light on many important aspects of our earth’s climate system. But at this point there is no more need for continued debate over the causes. We are now more certain than ever that burning fossil fuels and deforestation are responsible for the warming of the planet and its oceans, leading to the melting of glaciers, the retreat of arctic sea ice, the rise in sea levels, and the increased occurrence of extreme weather events.