A global reference point to what the science is saying about climate change is the United Nations Intergovernmental Panel on Climate Change special report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways. The report was published in October 2018, and in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty.
You can read it here: ‘Global Warming of 1.5°C’
For a verbal overview of the climate science, see the David Spratt’s Powerpoint presentation, Why is emergency-scale action necessary?
Global temperatures and baselines – NASA’s temperature spike graph
The raw data for this graph is found at: www.data.giss.nasa.gov/gistemp/graphs_v3/Fig.C.txt
Antti Lipponen, a researcher at the Finnish Meteorological Institute, has compiled weather statistics between 1900 and 2016 and turned them into a 35-second video. The results back up what climate scientists have been saying for decades – the planet is warming up.
Below is another way of showing the data:
Image by Antti Lipponen
Different graphs – different baselines
The graph above uses the average temperatures of the period from 1880 to 1909 as its 0°C baseline.
Other graphs showing this data from NASA use the average of 1950-1980 temperatures as the baseline.
In February 2016, the global temperatures spiked to 1.6°C over the 1880-1909 baseline.
This is the same as 1.35°C over the 1950-1980 baseline.
Since the period 1880-1909 was roughly 0.2°C warmer than the mid-17th century pre-industrial average temperature, the February 2016 global average temperatures was actually 1.8°C above the real pre-industrial temperature.
You will see various temperature rises mentioned in material from IPCC and in other climate science documents and media articles. Unfortunately none of them use a consistent baseline. The temperature rise figures cited vary depending on which baseline is being assumed.
March 2017 fourth warmest of any month in recorded history
NASA’s global temperatures data for March 2017 shows the month was 1.37°C degrees above a 1880-1909 baseline, making it the fourth warmest anomaly of any month in recorded history.
The six warmest months on record since 1880 were all in the last two years:
February 2016: 1.57°C
March 2016: 1.53°C
January 2016: 1.38°C
March 2017: 1.37°C
February 2017: 1.35°C
December 2015: 1.35°C
» Source: NASA dataset (Note: NASA uses a 1951–1980 baseline)
The figures below were provided by David Spratt on 13 September 2016.
RECORD HOT AUGUST, AND YEAR TO DATE
NASA today released its temperature data for August 2016.
It was 0.98°C warmer than the mid-20th century average.
This makes August 1.23C warmer than the 1880-1909 baseline (when observational records commence).
It is also the hottest August on record.
NASA says: “August 2016 was the warmest August in 136 years of modern record-keeping, according to a monthly analysis of global temperatures by scientists at NASA’s Goddard Institute for Space Studies (GISS) in New York.”
In addition: “The record warm August continued a streak of 11 consecutive months dating back to October 2015 that have set new monthly high-temperature records.”
Based on the 1880-1909 baseline, recent figures are:
2013-2015 average of 3 years: 1.01C
2015 year: 1.12C
Jan-March 2016 (El Nino peak): 1.51C
February 2016 (hottest month on record): 1.6C
Average for Jan-August 2016: 1.31C
First eight months of this year:
Note: for full pre-industrial figure (from mid-18th century), add 0.2C to all the above figures.
» The Conversation – 20 April 2017:
We need to get rid of carbon in the atmosphere, not just reduce emissions