Named after the Japanese city where negotiations were concluded on December 11, 1997, the agreement resulted in the first legally binding targets for dozens of developed nations to reduce or slow the growth of their greenhouse gas emissions.
Developing nations were excluded from such obligations and, in the early 2000s, the US — at the time the world’s biggest emitter of greenhouse gases — decided not to ratify the treaty. Canada also went on to withdraw from the protocol.
Niklas Hoehne, founder of the German think tank the NewClimate Institute for Climate Policy and Global Sustainability, said despite this “major failure” to include the US, the protocol had many achievements, especially in the EU, which “took it seriously and wanted to comply”.
“In the European Union, it initiated a whole set of policies that significantly changed the climate policies of the [bloc],” he said.
“Without the Kyoto Protocol, there wouldn’t be emissions trading, effort sharing [the EU’s mechanism for allocating greenhouse gas commitments to member states], car standards, a whole set of new policies.”
The Kyoto Protocol was struck five years after the landmark “Earth Summit” in Brazil, where nations agreed on the UN Framework Convention on Climate Change (UNFCCC), which set up the structure for dealing with the issue.
The protocol was designed to achieve the UNFCCC’s aim of stabilising greenhouse gas concentrations at a level that limited harm.
Under the protocol, 41 industrialised nations and the EU pledged that, by 2012, they would cut emissions of six greenhouse gases by an average of 5.2 per cent compared to 1990 levels.
There were many ways in which emissions reductions could be achieved, including investing in clean technologies in developing nations, something known as the clean development mechanism.
Although it later refused to ratify the protocol, the US was central to designing it, said Michael Grubb, professor of energy and climate change at University College London.
Al Gore, the US vice president at the time, took part in the negotiations, and the treaty was signed by Bill Clinton, a Democrat, in late 1998. But there was heavy opposition to the measure in the US Senate.
“The Republicans always said the US had overcommitted, the target was too ambitious and it made no sense without the developing countries,” Dr Grubb said.
George W Bush criticised the treaty during his campaign for the US presidency in 2000 and, in March the following year, not long after moving into the White House, he said his country would not enact the agreement.
In 2005, when the protocol came into effect, annual US carbon dioxide emissions from fossil fuels and industry were 6.14 gigatonnes (with one gigatonne equal to one billion tonnes), while those of the EU were 4.31Gt, OurWorldinData reports.
Between 2005 and 2021, the US and EU showed similar reductions in absolute terms, their emissions falling to 5.01Gt and 3.14Gt, respectively. In percentage terms, however, the EU achieved a faster decrease of 27 per cent, compared to 18 per cent for the US.
The omission from the protocol of China was significant. Lumped in with developing nations, it was exempt from the treaty’s requirements — only for its emissions to soar at a rate unseen before.
In 1997, when the protocol was agreed to, China pumped out 3.57Gt of CO2 from industry and the burning of fossil fuels.
By the time the protocol passed into law in 2005, this had risen to 5.88Gt, and a year later, China overtook the US as the world’s biggest emitter.
After further steep rises, the country’s CO2 emissions last year were estimated at 11.47Gt, but the NewClimate Institute has projected they will peak in 2025.
When the negotiations for the Kyoto Protocol started and the original framework convention was developed, it was “a very different world”, said Dr Grubb.
“Developing countries’ emissions were fairly small on an absolute basis … and the treaty said this problem has been caused by emissions from the industrialised world and they have the responsibility,” he said.
The Kyoto Protocol was, he continued, in part about developed countries, especially those in the EU, showing that it was possible to continue to develop while limiting emissions.
This was demonstrated by the “revolution in renewables”, as Dr Grubb described it, that came in the protocol’s wake.
Echoing this, Edgar Hertwich, a professor in industrial ecology at the Norwegian University of Science and Technology, credits the protocol with improving energy efficiency and pushing forward wind and solar power.
The protocol was, however, “really weak in what it was aiming for”, he said. As well as the absence of emissions reductions for scores of developing nations, targets for developed countries were “quite modest”.
While its goals were reached, Dr Hertwich said it was unclear how much the protocol was actually the cause for this. The process, he said, “could have gone a lot faster”.
“I think in the end the story will be one of a missed opportunity because there wasn’t enough will back then to act strongly,” he said.
“I think the Paris Agreement is in a sense a much better set-up. OK, it doesn’t have the same national targets for emissions that the Kyoto Protocol had, but at the same time it does [have] a dynamic mechanism for ratcheting up commitments by national governments.”
The Paris Agreement, struck in 2015, included both developed and developing nations and had more ambitious long-term goals “but pretty fuzzy implementation”, Dr Grubb said.
Unlike the Kyoto Protocol, it did not create legally binding targets, reflecting the tension between getting an agreement that is broad and one that is deep.
“By then , developing countries were worried about climate change. They still felt it should be some other countries’ responsibility, but they did want to try to find a way forward,” he said.
“The more countries you have on board, the weaker the structure is going to be. That’s almost unavoidable.”
As part of the Paris Agreement — the first proper stocktaking of which is set to happen at Cop28 in the UAE in late 2023 — countries put forward Nationally Determined Contributions, their pledges on what action they will take to reduce emissions and adapt to climate change.
These are put forward by nations knowing that they will not be held legally accountable, Dr Grubb said, and implementation can be especially problematic if there is a change of government, as an incoming administration may not feel obliged to adhere to the commitments of its predecessor.
There are, then, both pluses and minuses to the Kyoto Protocol and its successors.
Despite its faults, the Kyoto Protocol in the form that it was agreed to was “an essential first step”, Dr Hoehne said, given that in 1992, five years before it was signed, the decision had been made that developed countries should act first.
“Therefore it was a very important step along the way,” he said. “I’m sure it paved the way towards agreements with all countries.”