Our Man in Warsaw: Day 2 - The value of carbon budgets


Remember when we called climate change ‘global warming’? It made sense, since heat-trapping gases create a greenhouse effect and cause global average temperatures to increase over time.

As any linguist will tell you, language affects our perceptions and how we define reality. Global warming is no exception.

This focus on warming led the UN climate change process to be framed by temperature targets rather than emissions targets. In Cancun in 2010, most countries agreed that staying below a 2°C temperature rise above pre-industrial levels was a safe enough course, so temperature control became the goal.

Emissions targets were always more contentious than temperature ones anyway, since they quickly led to talk about allocation sharing, which is tricky business. But this formal disconnect between temperature and emissions made it hard to know how much action on climate change was needed, and how far off course we’d strayed.

In its latest report, the Intergovernmental Panel on Climate Change (IPCC) developed a global carbon budget that makes explicit the relationship between carbon and temperature. The idea of a global carbon budget makes the challenge very relatable, too, since people are familiar with managing their own personal budgets.

For a 50% chance of staying below 2°C, the IPCC says we can emit a cumulative total of 1.21 trillion tonnes of carbon (for a 33% chance, it’s 1.56 trillion tonnes, and 66% chance is 1 trillion tonnes). Most people are shooting for 50:50 odds.

We’ve already emitted 531 billion tonnes since the industrial revolution, so we have about a 600 billion tonne carbon budget left to spend.

Last year, humans released 50 billion tonnes CO2e, so at the current rate, we have 30 years until we start overdrawing from our carbon account and push up the chances of breaking through the 2-degree limit.

The budget was made very tangible in the UN Environment Programme’s latest Emissions Gap Report, which shows different scenarios that can keep the world inside the budget up to 2100. They’ve even got a Gap App you can download.  

The tool shows where we are now, where our current trajectory takes us by 2020, and what options keep us within the budget. If every country’s emission reduction pledges are achieved, we’re still left with a pretty big gap from what’s required. We need to reduce an additional 8-12 billion tonnes over and above current pledges to stay within our carbon budget by 2020. 

That’s a lot. But this gap tool shows how it can be done, broken down by sector and using current technology. Disaggregating the challenge this way makes a daunting task seem a lot more achievable.

By moving forward with low carbon energy technologies, improving efficiency in industry, buildings and transport, treating waste more effectively, slowing deforestation and adopting lower-carbon farming practices, we can shave billions of tonnes of carbon off the world’s emissions. Even better – most of these actions save money or improve productivity, and tend to have fairly short payback periods.

That’s the message that is loud and clear here in Warsaw – we have the technology and know-how to stay within our 2020 budget, and the money is out there. We just need to overcome intangible barriers like lack of awareness, risk perceptions, access to finance, and others.

The Carbon Trust is good at figuring that out, as are other organisations in other countries. If we work together and move forward with implementation, we might still have some carbon left in our budget when 2020 rolls around.  

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