The conversationJune 17, 2021 1:02:52 PM IST
The four-day G7 summit in Cornwall ended with little cause for celebration from anyone concerned about climate change. Most of the promises that emerged were relatively old news, with the UK repeating its £ 500 million pledge for ocean conservation efforts and the group reaffirming its commitment to end support for the production of coal abroad.
The leaders of (supposedly) the richest democracies in the world failed again accept new funds to help the poorest parts of the world invest in green technology and adapt to extreme weather conditions.
But more interesting than these promises and non-promises were the things that were not mentioned at all. One of the biggest unspeakable at the climate summit after the climate summit is how poorly we track contributions to global warming.
It is the elephant in the room at any meeting where leaders of rich countries discuss climate change: historical responsibility. Everyone knows that the G7 nations have contributed disproportionately to the global warming that has already occurred. But exactly how much more?
If you search online For which country has caused the most global warming, you will find a list of the number of countries that emit each year. Dig deeper and the next thing you’ll find is how much they have reduced their emissions since 1990. This favors mature economies whose emissions are declining. But for carbon dioxide, whose effects last almost indefinitely (and to a slightly lesser degree, nitrous oxide, a by-product of fertilizer production and use), it is the emissions accumulated over time that determine the contribution from a country to global warming, not emissions in any given year.
Focusing on current broadcasts is particularly kind to the G7 host. UK emissions have dropped dramatically since 1990, but the country started burp carbon dioxide out of its dark satanic mills nearly 100 years before the rest of the world realized it. A ton of carbon dioxide emitted by an English cotton mill in 1800 is today having exactly the same impact on global temperature as a ton of carbon dioxide emitted by a Vietnamese power plant in 2021.
Brazil promoted in effort quantify country-level contributions to global warming in the 2000s, but was quietly allowed to die. Currently, the United Nations Framework Convention on Climate Change (UNFCCC), the main forum for international climate action, only requires countries to report their contributions to emissions, not warming. And everyone else, from corporations to personal carbon footprint calculators, follows suit.
“Is not the same?” you might ask. Unfortunately, No. The method that the UNFCCC has chosen to report emissions reflects its effect on the balance between the energy the Earth absorbs from the Sun and the energy it emits into space during the 100 years after the date of emission. This is somewhat related to its effect on global temperature, but it is far from the same.
For emissions that accumulate in the atmosphere over decades or centuries, such as carbon dioxide and nitrous oxide, the distinction does not matter. But for methane and a host of other climate pollutants that persist from a few days to a couple of decades, of great importance. Any country that is contemplating the creation of a hydraulic fracturing industry (notorious for methane leaks) can rest assured that it will be 100 years before the warming effect of their fugitive methane emissions is accurately reflected in their reports to the UNFCCC.
Landing the plane with one eye closed
In the Paris Agreement, the world set itself a very ambitious goal. The main objective is not about emissions, but to limit the increase in global average temperature to “well below 2 ° C”, making efforts to limit warming to 1.5 ° C if possible.
That is good. In general, the effects of climate change depend on how much we warm the planet in general, not on warming on a certain date, or the rate of emissions and warming at a given time, and certainly not on the planetary energy imbalance added over a time horizon arbitrary. . But right now, it is impossible to take stock of progress towards this temperature target because countries, in their plans for 2030 and beyond, only report aggregate emissions using this rather strange accounting system that does not reflect the effect of these emissions. in global temperature. .
If rich countries like the G7 are serious about stopping global warming, a good start might be to clarify who and what is causing it. There is no prospect of the UNFCCC changing its accounting system, but it allows countries to present additional information if they consider it relevant.
And what could be more relevant than the actual contributions to global warming? At COP26, the Glasgow climate conference in November 2021, the G7 nations could step up and declare that from now on they will report, in addition to their emissions, how much warming they have already caused, how much they continue to cause, and how much they propose. . cause in the future.
All the information exists. Contributions to warming can be calculated using exactly the same formulas used for the UNFCCC’s own emissions reporting. It’s simply a matter of posting the numbers and encouraging everyone else to do the same.
It’s not just about exposing the guilty rich. Recognizing what is causing the warming should focus attention on what it takes to stop it. And if we add the planned contributions of the G7 to future warming, regardless of the contributions of China, India and the rest, it will soon become clear that not only do we need to stop causing global warming as soon as possible, but we also need to be able to reverse it by taking out the dioxide. of carbon from the atmosphere and storing it, No danger other permanently, somewhere else. Another topic that they prefer to avoid in the climatic summits.
Myles allen, Professor of Geosystem Sciences, Director of Oxford Net Zero, University of Oxford