The climate pledges submitted to the UN by individual countries don't do enough to reduce global greenhouse emissions and hold warming below 2 degrees, according to Climate Action Tracker (CAT), a consortium of climate scientists and policy experts.

This week, delegates are meeting in Bonn for some of the last days of talks before the much-anticipated UN climate conference in Paris this December. CAT took the opportunity to underscore that countries must pledge more to make the agreement a success.

The UN has made general recommendations for the climate agreement. But these are not binding. The success of the global agreement depends on each nation's ambition to reduce greenhouse gas emissions.

By September 4, 58 countries had submitted their "intended nationally determined contributions" (INDCs), including 95 percent of developed countries. But altogether, these countries are responsible for only around 62. percent of global emissions.

According to experts from Climate Analytics, one of the organizations that make up the CAT consortium, most governments that have submitted their pledges so far need to strengthen them. Those who are yet to pledge must aim to reduce carbon emissions as much as possible. Otherwise, Climate Analytics warns, the target of keeping global warming below 2 degrees Celsius will be missed.

The pledges don't follow a standard rule. Each country determines its own contribution according to its national priorities, domestic circumstances and capabilities. Through the INDCs, these contributions are communicated internationally as the steps it will take to address climate change and contribute to a low-carbon, climate-resilient future.

Countries may also include their strategy to cope with climate change impacts and indicate what support they need, or what support they can provide to help other countries reduce their greenhouse gas emissions to reach global targets.

CAT has assessed the INDCs submitted so far according to factors including the size of the country, their current emissions, level of industrialization and economic growth, among others. It found that seven were "inadequate," rated six as "medium" and judged only two to be "sufficient".

Here's how the pledges of the seven biggest greenhouse gas emitters measure up, according to CAT:

China: medium

China has pledged a peak in carbon dioxide emissions by 2030, and "best efforts" to peak earlier. It also pledged to source 20 percent of its energy from low-carbon sources by 2030, and to cut emissions per unit of GDP by 60 to 65 percent by 2030 on 2005 levels, potentially putting it on course to peak by 2027.

United States: medium

The United States pledged a domestic reduction of 26 to 28 percent in greenhouse gases by 2025, compared to 2005 levels, making its "best effort" to reach the 28 percent target. This includes the land-use sector and excludes international emissions credits at this time.

European Union (28 countries): medium

The European Union has pledged at least a 40 percent domestic reduction in greenhouse gases by 2030, compared to 1990 levels.

Mexico: medium

Mexico has made an unconditional pledge to reduce greenhouse gases and short-lived climate pollutants by 25 percent compared to a business-as-usual scenario, by 2030. This could rise to 40 percent, subject to the outcome of a global climate deal. For the unconditional pledge, this means a net emissions peak by 2026, and reducing emissions intensity per unit of GDP by around 40 percent from 2013 to 2030.

Japan: inadequate

Japan has pledged a 26 percent reduction in greenhouse gas emissions by 2030 on 2013 levels. The INDC submission includes precise information on how it will generate its power by 2030.

Russia: inadequate

The Russian Federation submitted a pledge to reduce domestic greenhouse emissions by 25-30 percent by 2030, compared to 1990 levels. It includes "maximum possible account" of the land-use sector.

Canada: inadequate

Canada is the world's biggest greenhouse gas emitter per capita. It has pledged a 30 percent reduction in greenhouse gas emissions by 2030, compared to 2005. This includes the land-use sector and forestry, as well as possible use of international emissions credits.

Setting a bad example

Marcia Rocha, Climate Analytics' climate policy team leader, said those responsible for the lion's share for climate-harmful emissions were setting a poor example.

"The leadership that smaller and developing country parties can expect from the major economies and largest emitters is still largely insufficient to provide the impetus needed to accelerate the negotiations and raise collective ambitious action," she told DW.

Low-emitting countries often bear the brunt of climate impacts

The next highest emitters yet to submit INDCs are India, Brazil, Iran, Indonesia, Saudi Arabia, South Africa, Thailand, Turkey, Ukraine, and Pakistan. Together they account for 18 percent of global emissions not yet covered by INDCs, excluding land-use, land-use change and forestry activities (LULUCF).

Even if these countries show more ambition, it won't be enough unless the big players do their bit, Rocha said. "Independently of what the other countries in the world put forward, the gap cannot not be closed without more ambitious reductions coming from [the major greenhouse gas-emitting economies]."