Global Warming: Future greenhouse gas emission scenarios

The future of our carbon dioxide and greenhouse gas emissions will decide how many degrees will planet Earth be warmer by 2100 (relative to pre-industrial temperatures). Using the data from Climate Action Tracker, the online publication that shows how living conditions are changing, Our World In Data has published a chart showing future greenhouse gas emission scenarios and how each scenario would result in an estimated global warming by 2100.

Greenhouse Gas Emissions
To limit the global warming to 1.5-2 °C by 2100 (relative to pre-industrial temperatures), we’d need an urgent and rapid reduction in global greenhouse gas emissions. Image: PX Here

Related: We emit so much carbon dioxide into the earth’s atmosphere that only planting trees is not enough

Five future greenhouse gas emission scenarios

What does the future of our carbon dioxide and greenhouse gas emissionsNotes 1 look like? In the chart below, it has been shown a range of potential future scenarios of global greenhouse gas emissions (measured in gigatonnes of carbon dioxide equivalents), based on data from Climate Action Tracker. Here, five scenarios are shown:

  • No climate policies: projected future emissions if no climate policies were implemented; this would result in an estimated 4.1-4.8°C warming by 2100 (relative to pre-industrial temperatures).
  • Current climate policies: projected warming of 3.1-3.7°C by 2100 based on currently implemented climate policies.
  • National pledges: if all countries achieve their current targets/pledges set within the Paris climate agreement, it’s estimated average warming by 2100 will be 2.6-3.2°C. This will go well beyond the overall target of the Paris Agreement to keep warming “well below 2°C”.
  • 2°C consistent: there are a range of emissions pathways that would be compatible with limiting average warming to 2°C by 2100. This would require a significant increase in the ambition of the current pledges within the Paris Agreement.
  • 1.5°C consistent: there are a range of emissions pathways that would be compatible with limiting average warming to 1.5°C by 2100. However, all would require a very urgent and rapid reduction in global greenhouse gas emissions.

Interactive data of these pathways is below:

Global future greenhouse gas emission scenarios
Potential future scenarios of global greenhouse gas emissions (measured in gigatonnes of carbon dioxide equivalents) in the case of no climate policies, currently implemented policies, national pledges within the Paris Agreement, and 2°C and 1.5°C pathways. High, medium and low pathways represent ranges for a given scenario. Temperature figures represent the estimated average global temperature increase from pre-industrial, by the year 2100. Image: Our World In Data

Notes

  1. A greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect (the process by which radiation, from a planet’s atmosphere, warms the planet’s surface to a temperature above what it would be without its atmosphere). The primary greenhouse gases in Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Without greenhouse gases, the average temperature of Earth’s surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F).

Sources

  • Hannah Ritchie and Max Roser (2018) – “CO₂ and other Greenhouse Gas Emissions”. Published online at OurWorldInData.org
  • Greenhouse gas on Wikipedia

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