• Ian Sutton

IPCC Report: Global Warming of 1.5°C

This blog is based on the post IPCC Report: Global Warming of 1.5°C.


The IPCC (Intergovernmental Panel on Climate Change) issues reports to do with climate change on a regular basis. The post The IPCC and Its Reports lists five of the most recent and significant of these reports. They are:

  • Global Warming of 1.5°C (2018);

  • Climate Change 2021: The Physical Science Basis;

  • Climate Change 2022: Impacts, Adaptation and Vulnerability;

  • Climate Change 2022: Mitigation of Climate Change; and

  • Sixth Assessment Fact Sheet.

In this post we consider the first of these reports: Global Warming of 1.5°C.

The phrase ‘Net Zero by 2050’ comes from what is probably the best-known IPCC report, Global Warming of 1.5 °C. That report, which was published in the year 2018, contains the following remarkable sentence.

In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range).

< my emphasis >

As discussed in the post A Clunky Sentence, the above sentence is incomprehensible. Yet it is profoundly important.

The term ‘Net Zero by 2050’ has been adopted by organizations all over the world (which is why it is used in the title of this book series). Although there is nothing inherently special about the words ‘Zero’ or ‘2050’ both are pithy and memorable, so they provide an easy-to-grasp target if only because they contain plenty of zeroes. (The use of the word ‘net’ means that organizations that continue to emit greenhouse gases can compensate by removing an equivalent amount in some other way. In practice this means that they need to invest in Direct Air Capture facilities.)

The year 2050 is, of course, an arbitrary deadline. The forces of nature have no interest in the targets that we create. Mother Nature/Gaia is going to do what she wants to do both before and after the year 2050. Moreover, the year 2050 is a long way away. It can be used as an excuse to avoid taking action now.