The recent IPCC AR6 WGI report summarises the state of knowledge of physical climate science, but the final version of the Summary for Policymakers (SPM) did not include a figure showing a range of indicators of our warming planet.
An earlier draft of the SPM included a figure like that below which aimed to put recent changes into a longer context of changes over the past 2000 years, and to show how other climate metrics have changed in recent decades. Many of these time series were shown in disparate places of the report, and have been brought together in this updated graphic which also indicates key milestones and discoveries in climate science.
To avoid reaching global temperature levels such as 1.5°C there is a limited amount of carbon dioxide we can emit into the atmosphere. We are rapidly using up this ‘carbon budget’, mainly by burning fossil fuels and deforestation.
The figures in the IPCC AR6 WGI SPM are a huge improvement over previous reports. However, one minor quibble is with the lack of observations shown. This brief post makes a figure available which is based on IPCC AR6 WGI SPM Figure 8, but with some observations added to show how global surface temperature and Arctic sea ice area have varied, compared to the model simulations. In my view this is a scientific improvement over the original version. Continue reading Adding observations to IPCC figures→
The Working Group I (WGI) component of the IPCC 6th Assessment Report (AR6) has been released. One key development since AR5 was the involvement of professional graphic designers in creating the figures for the Summary for Policymakers (SPM). As a result, the graphics are clear and usable, having been user-tested through several design iterations. The data underlying the figures are also openly available. Continue reading IPCC SPM Figures→
In December 2019, the average temperature across Australia was about 2°C above what would be expected for the present-day, which is another 1.5°C above temperatures that were normal for December before humans started warming the climate. These extreme temperatures have contributed to the catastrophic bushfires which have devastated large areas.
But what may be considered ‘normal’ is constantly changing.
In a world which has warmed by 3°C – roughly the current global trajectory – what was extreme will be entirely normal.
The lower atmosphere is warming while the upper atmosphere is cooling – a clear fingerprint of the enhanced greenhouse effect from human emissions of carbon dioxide.
The simple explanation is that some of the infrared radiation emitted by the surface, which would have normally reached the upper atmosphere, is absorbed by greenhouse gases in the lower atmosphere. The upper atmosphere therefore receives less energy than before, and so cools. The very warm years (intense reds) in the upper atmosphere are the 1982-83 El Chichón and 1991-92 Pinatubo eruptions respectively.
On 21st June 2019, the #ShowYourStripes initiative was launched, providing ‘warming stripe’ graphics for virtually every country at showyourstripes.info.
The data was provided by Berkeley Earth and several national meteorological agencies, and the stripe graphics are available for 1901-2018 for most locations, but extended further backwards where the national data was easily available. The US States and UK regions have their own separate graphics, as do Stockholm, Oxford and Vienna – three of the longest continuous series in Europe.