On October 8, the UN Intergovernmental Panel on Climate Change (IPCC) issued its final special report on the impacts of global warming above 1.5 Celsius above pre-industrial levels. The process of compiling this report began back in April 2016 in order to help strengthen efforts to combat global warming that were agreed to at the Paris Climate Conference. The report spans 5 chapters, each discussing different aspects. Chapter 1 provides context and discusses the establishment of 1.5 degrees Celsius as a level of discussion as well as pathways towards trying to remain below that critical level. Chapter 2 discusses mitigation methods in terms of sustainable development. The impact on humans and the natural world system provides the subject for Chapter 3. The focus of strengthening the existing response is covered in Chapter 4. Finally, Chapter 5 discusses reducing inequalities such as poverty. The report was prepared by 91 different authors and review editors from over 40 countries and includes more than 6000 scientific references
Some might take the report as alarmist, but it is merely demonstrating through scientific analysis and observable fact, that the planet has already shown impact from warming of 1 degree Celsius. The extreme weather patterns, rising sea levels, and shrinking arctic sea ice are some of the visible changes that have occurred due to warming since the Industrial Revolution. One of the main purposes of the report is to demonstrate that there are differences that will occur if we can limit the increase in global warming to 1.5 degrees Celsius rather than allowing it to increase to 2 degrees Celsius or more. That 1/2 degree Celsius difference could result in global sea rise of 10 cm less, a once in a century chance of no Arctic Sea ice in the summer rather than a once a decade chance, 70-90% loss of coral reefs versus greater than 99% loss, and more.
The good news is that the types of efforts that are needed to prevent warming of more than 1.5 degrees Celsius are already underway. The bad news, and the real source of importance in this report, is that the efforts need to be accelerated exponentially in order to assure any form of success. Global net emissions of carbon dioxide caused by humans would need to fall approximately 45% from 2010 levels by 2030 and reach that all important net zero level by 2050. Failure to prevent the warming level from rising above 1.5 degrees Celsius would require greater reliance on efforts to remove existing carbon dioxide from the atmosphere in order to return to that 1.5 degree level by 2100. The problem is that although there are efforts underway to come up with solutions for removing carbon dioxide from the atmosphere, these methods are unproven and have not been tested on the large scale that would be required.
The report estimates with high confidence that we will reach the 1.5 degrees Celsius mark between 2030 and 2052 if the increase continues at the current rate. The warming from emissions dating back from the industrial revolution until the present are expected to remain for centuries to millennia and will continue to cause changes to the climate system; however, the report states with medium confidence that these emissions alone are unlikely to cause warming of 1.5 degrees Celsius. Ultimately, the report tells us that we need to do more and we need to do it quicker in order to prevent an increase in global climate that could be even more problematic.