The Himalayan kingdom of Bhutan has made the world’s most far-reaching climate promise to the Paris climate summit, according to new analysis from a respected climate change thinktank.

Almost three quarters of the mountainous nation is covered in forests, often watered by snowmelt rivers, and Bhutan has pledged to reforest its land even further. Last summer, it set a world record for the most trees planted in one hour – nearly 50,000.

According to the ‘carbon comparator’ tool developed by the Energy and Climate Intelligence Unit (ECIU), the country is now an unparalleled carbon sink, absorbing three times more CO2 emissions than its 700,000 population produces, mostly through hydropower. A substantial portion of the country lacks access to the electricity grid, however.

Richard Black, the ECIU’s director, told the Guardian that the country’s push on agroforestry made sense because of its acute vulnerability to climate change.

“As a small state high in the Himalayas, Bhutan faces disruption to water supplies, extreme weather and impacts on ecosystems as a result of changes to the climate, so it is in their interests to address the problem both domestically and through the UN climate process,” he said.

Bhutan, which tests all policies and projects against a Gross National Happiness index, has promised to keep at least 60% of its forest cover “in perpetuity”.

Beyond agroforestry, the country is planning steps to combat the regional growth of ‘car culture’ including heavy automobile taxes, public transit systems and greater use of electric vehicles.

Thinley Namgyel, the country’s chief negotiator in Paris, said public concern about climate change had been a key policy driver, in a country dominated by small subsistence farmers.

“People are already noticing the temperature changes,” he said. “High mountains which should be closed for months are now open year-round. Monsoon rains are not arriving on time, and then appearing when we don’t need them, destroying crops.”

Many water sources outside forest areas were drying up for reasons unknown, Namgyel said, while flash floods were intensifying.

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“We see a huge [potential] disaster developing from the mountain glaciers, which are retreating,” Namgyel said. “This threatens people in settlements downstream, as well as the hydropower that we depend upon.”

Preserving biodiversity has knock-on benefits for agriculture, waterways, ecosystem services and general resource wealth, that need not be directly related to climate change. It could, for example, aid regional exports, Black said.

The ECIU’s carbon comparator’ tool provides a searchable database, allowing national climate records and policy commitments to be compared across 36 metrics.

The searches cross-reference climate data supplied by over 190 nations to the UN, World Bank and World Resources Institute.

Other surprises to leap out of its databanks include a finding that Paraguay is the world’s leading provider of low carbon energy, generating almost 100% of its energy from hydropower, some of which it exports to its neighbours.

North Korea has cut its emissions by around 54% since 1990, according to its INDC, although this would not be an example many wish to emulate, even if it can be verified.

“North Korea’s emissions collapsed in the mid-to late 1990s as a result of the failures in the country’s economic model, which led to famine,” said Bill Hayton, an associate fellow at Chatham House’s Asia Programme. “Industrial production declined along with most other forms of energy consumption, so what appears like success is actually failure.”

Another surprise is that Europe’s richest country, Luxembourg, generates four times more CO2 emissions than Bhutan, despite having a smaller population.

France’s record compares well with most countries due to its reliance on nuclear energy, which is relatively low, and an expanding role for renewables in its energy mix.

In terms of scale though, these are dwarfed by China’s plans to bring 200GW of wind and 100GW of solar energy into the national grid by 2020, while peaking coal emissions.

“It has been a massive turnaround in the last four years,” Black said. “Our analysis of the INDCs suggests that the eventual figures from China will be a lot bigger than even that.”