The CAT Thermometer explained
The temperatures on the CAT thermometer are ‘median’ warming estimates in 2100. It means that there is a 50% chance that the calculated temperature would be exceeded if the given emissions pathway were followed.
For example, our emissions pathway in the pledges and targets scenario gives a 50% chance of warming being 2.8°C or higher in 2100.
Using probabilities to provide more information
The ‘median’ is based on the probability distribution generated by the climate model (MAGICC) when it takes into account uncertainties in our knowledge of climate sensitivity, the carbon cycle, and effect of greenhouse gases, aerosols, and other factors that are used to calculate the temperatures. The probability distribution enables us to provide more information for policy makers and stakeholders about the likelihood of goals being met, or specific temperatures being exceeded.
December 2019 NDCs likely below 3.0°C and over 90% chance exceeding 2°C
The emissions pledge pathway that includes NDCs has over 90% probability of exceeding 2°C. The current policy pathways have a higher than 97% probability of exceeding 2°C.
What governments need to do to achieve the global goal
The IPCC Special Report on 1.5°C shows that steep emissions reductions are urgent, but feasible, and will still deliver the many benefits associated with 1.5°C-compatible pathways in terms of avoided climate-change impacts, as well as cleaner air, increased employment in the renewable energy sector, access to modern energy, etc.
The IPCC Special Report on 1.5°C shows that even starting from emission levels implied by NDCs and current policy projections, 1.5°C and 2°C pathways are still technically feasible. However, the resulting emission pathways are increasingly expensive as they are not consistent with the most cost-efficient policies. Slower-than-optimal emission reductions early on need to be followed by faster reductions later on, effectively leading to significantly higher costs for the period 2030–2050 than would otherwise be needed. While the challenges are significant, limiting warming to below 1.5°C by the end of the century is still feasible from current emissions levels. However, with every decade lost, these challenges and costs rise and will, at some point, become insurmountable with warming locked in to 1.5 or 2°C and above.
For more information on the global emission pathways and how they are calculated, please see the detailed analysis and methodology pages.
If you use the provided data or any of the graphs provided on this website, please make sure to reference the Climate Action Tracker and the Climate Analytics / NewClimate team!
Last update: 10 December 2019.