Only One Number Matters – 95 Percent

This post is adapted from Maggie Fox’s blog article entitled More Certain Than Ever. Maggie Fox is the CEO of the Climate Reality Project and a blogger.

The Intergovernmental Panel on Climate Change (IPCC) has now realeased the first part of its fifth assessment report (known in the field as AR5).

The report represents, in many respects, the verdict on what we know about climate change from the planet’s leading climate scientists. Over 800 experts representing 85 countries have spent the past several years reviewing the climate research happening all around the world and distilling the results into a series of reports that reflect the combined wisdom of the field. The verdict: man-made climate change is a reality.

Some Findings from the Report

• Global warming is “unequivocal,” and since the 1950’s it’s “extremely likely” that human activities have been the dominant cause of the temperature rise.
• Concentrations of carbon dioxide and other greenhouse gases in the atmosphere have increased to levels that are unprecedented in at least 800,000 years. The burning of fossil fuels is the main reason behind a 40 per cent increase in cabond-dioxide concentrations since the industrial revolution.
• Global temperatures are likely to rise by 0.3 to 4.8 degrees C, or 0.5-8.6 F, by the end of the century, depending on how much governments control carbon emissions.
• Most aspects of climate change will continue for many centuries even if carbon-dioxide emissions are stopped.
• Sea levels are expected to rise a further 26-82 centimetres by the end of the century.
• The Greenland and Antarctic ice sheets have been losing mass over the past two decades. Glaciers have continued to melt almost all over the world. Arctic sea ice has shrunk and spring snow cover has continued to decrease, and it is “very likely” that this will continue.
• It’s “virtually certain” that the upper ocean has warmed from 1971 to 2010. The ocean will continue to warm this century, with heat penetrating from the surface to the deep ocean.

Reactions to the report have been widespread. World leaders, politicians, scientists, the news media, bloggers, and of course, deniers from every corner of the globe have been quick to find snippets from the Report which can best represent their respective opinions and points of view. Needless to say that the confusion, inaction and overall inertia which have stalled any meaningful efforts to combat climate change, will continue. 

According to Maggie Fox,

Deniers have a habit of reading these reports with electron microscopes looking for any details they can rewrite to fit their message with the imagination of a Stephen King novel. To judge from early indications, this year’s report is no different. Expect to see places like the Wall Street Journal or the Daily Mail fill their front pages with claims AR5 shows climate change isn’t happening and quotes out of context about temperature sensitivity and a pause in global warming. These are smoke and mirrors designed to detract our attention from the core facts and nothing more.

The truth is, for those of us who don’t spend our lives in research labs, there’s only one number that matters: 95 percent. Because it really matters. When scientists got together and released the second IPCC report in 1995, they were about 50 percent certain that humans were driving climate change. Today, that number is 95 percent.

Think about this number

Yes, think about this number and let it sink in. Then apply it to your day to day life. You hear that your local weather report forecasts a 95% probability of rain. You might consider bringing an umbrella or rain protection as you go out the door. Or your car mechanic tells you that your brakes are 95% worn and have become a safety hazard. Do you simply ignore that warning?

95% is the mantra going forward, very much like 350 ppm CO2 or 2 degrees Celsius. Says Fox,

What makes the number stand out is that it doesn’t come from flag-burning protesters in the streets, climate advocates, or professional provocateurs with an agenda. It comes from climate scientists…who, by their nature, are quite a conservative bunch when it comes to conclusions—especially collective conclusions….their work has to hold up to public scrutiny and reflect the truth to the very best of their knowledge. After all, their reputations and careers, and integrity are on the line.

Then there’s the fact that the report’s findings reflect the unanimous agreement of hundreds and hundreds of scientists and government officials, many with vastly different political ideologies and world views.

We Are More Certain Than Ever Before

That such a large, diverse, and risk-averse group is able to state with 95 percent certainty that we are causing climate change tells you everything about the fundamental reality of the crisis. Climate change is real. It’s happening now. It’s human-caused. So when you read or hear anti-science deniers claim climate change isn’t happening or it’s not caused by anything we’re doing, remember the overwhelming majority of real experts agree on those three simple truths: and there’s mountains of data behind those truths.