Report 10, May 13, 2023
Goals to limit Global Warming to 1.50C change by 2050
The three major reports of the 6th Intergovernmental Panel on Climate Change (IPCC) have been issued. The first report presented the overwhelming scientific evidence that humans are responsible for recent increases in climate change. The second report established the scientific evidence of many of the specific changes in the Earth’s natural systems associated with climate change. The third report indicates in great detail, what human actions would limit increases in climate change. All three reports are based on scientific evidence prepared by hundreds of scientists and approved by representatives of over 150 national governments.
The most recent projections of the Intergovernmental Panel on Climate Change include eight scenarios on the future possibilities of global warming by 2100. projections C1 to C4 show global warming to remain below 20 C above the base of 2015. Categories C5 to C8 all exceed a peak global warming above 20 C. If major climate changes are to be avoided, the IPCC reports that climate warming must remain below 1.50C. Only scenario C1 attains that goal without an intermediate overshoot. (C2)
1.50 C is simply the increase above the climates of pre-industrial times. It is an arbitrary point, established as a goal in the Paris Treaty in 2015 and approved by 196 nations. Beyond 1.50 C, it will be extraordinarily difficult or impossible to reverse many of the changes caused by C02 emissions. If current practices are projected, by the end of this century, the increase in global temperatures may well reach 30C or greater. Any increase beyond 1.5 o C simply means that more unexpected changes in the Earth’s ecology will cause more disruptions of livability.
A. Possibly the most striking change from earlier reports is the necessity of reducing the consumption of fossil fuels by 50% in the next eight years if the increase in of greenhouse gases (GHG) is to be limited to less than 1.5o C.
A continued projections of current emissions (as shown in red) would result in an increase between 40C and 60 C. Only the line shown in blue indicates a 50% chance of reaching the 1.50 C goal by 2050.
B. To reach the 2050 goal would require steps such as those exemplified in the following diagram from Net Zero by 2050: A roadmap for the global energy system. Produced by The International Energy Agency, it is the most extensive report on how to reach the 2050 goals. In the forward to this report its director writes:
“We are approaching a decisive moment for international efforts to tackle the climate crisis – a great challenge of our times. The number of countries that have pledged to reach net‐zero emissions by mid‐century or soon after continues to grow, but so do global greenhouse gas emissions. This gap between rhetoric and action needs to close if we are to have a fighting chance of reaching net zero by 2050 and limiting the rise in global temperatures to 1.5 °C. Doing so requires nothing short of a total transformation of the energy systems that underpin our economies.”
C. The necessary changes to reach the 1.5 o C goal by 2050 in energy consumption by sector are great. In the industrial and building sectors, the overwhelmingly importance is in substituting electricity and renewables for fossil fuels. For the transport sector it is the replacement of oil by energy efficient electric vehicles. 
D. Looking at the time by which these changes must be made is shown in the next diagram from a report by Bloomberg.
E. Another way of thinking about the changes in several sectors of the economy that are needed to reach the 2050 goal is shown below.
F. Yet another way of thinking about the necessary changes is by looking at the energy substitutions.
In this report, I have indicated
1. the state of global warming, today, and
2. the reduction in fossil fuel energy that must be reduced to remain below the 1.5 C degree limits that the IGPCC says is necessary to limit increasing likelihood of unstoppable climate warming, and
3. examples of some of the actions needed to remain below 1.5 C degrees of global warming.
The next report will show the unlikelihood that the IGPCC goals can be met.