As the world wrangles over its next steps in fighting climate change, each country has its own concerns and interests they hope to advance at this year's U.N. climate summit.

U.N. climate negotiations can only pass deals with unanimous support from all countries present. That makes finding consensus a daunting challenge.

Here are some of the main players and negotiating blocs involved in the COP28 conference starting Nov. 30 in Dubai, Reuters reports.

CHINA

China leads the world in both clean and dirty energy, with more renewable energy capacity and more coal consumption than any other country. Responsible for about 30% of annual global emissions, China is the world's biggest greenhouse gas emitter.

The country is also suffering climate change impacts, including heatwaves and flooding, as well as extreme drought.

In climate negotiations, Beijing argues that wealthy developed countries like the United States, the biggest historical CO2 emitter, should move first and fastest in climate policy and finance.

Despite having the world's second largest economy after the United States, China considers itself as a developing nation in the climate talks.

UNITED STATES

The world's second-biggest emitter comes to COP28 a year into rolling out its $369 billion-plus subsidy package for electric vehicles and other green products. The Inflation Reduction Act (IRA) is expected to triple the country's clean energy capacity by 2030.

The U.S. and European Union are now asking others to join a COP28 pledge to triple renewable capacity this decade.

The United States - the world's biggest oil and gas producer - also supports a COP28 deal calling to phase out CO2-emitting fossil fuel use.

But U.S. delegates will face pressure for climate finance after Washington pledged no new climate cash to the United Nations this year. The U.S. supports creating a new fund to help poor countries deal with climate-caused damage, but wants the deal to make clear no country will be obliged to pay into it.

EUROPEAN UNION

The 27-country EU's negotiating position for COP28 is among the most ambitious. The bloc will push for tripling renewable capacity, phasing out CO2-emitting fossil fuels, ending new coal-fuelled power plants and powering electricity grids with renewable sources in the 2030s.

The EU also wants countries to agree that technologies to "abate" - meaning capture - emissions will only be used sparingly. That sets up a clash between the EU and countries that are reliant on fossil fuels and see abatement technology as a way to prolong their use.

At the U.N. climate talks, the EU bloc is traditionally allied with climate-vulnerable small island states. But the EU is at odds with those allies over some details of the climate damage fund.

The EU wants China and other large economies to pay into the planned fund, which Beijing opposes.

UNITED KINGDOM

Despite leaving the EU in 2020, the United Kingdom comes to COP with similar asks to the bloc - including on phasing out fossil fuels and tripling renewable energy.

This year, however, London raised eyebrows among some climate diplomats by weakening some green policies and approving 27 licenses for oil and gas exploration. The UK government says it is still on track to meet its climate targets.

'BASIC' COUNTRIES

Brazil, South Africa, India and China make up this bloc of populous, fast-developing countries. Each has asked for more climate financing and equity through the United Nations Framework Convention on Climate Change (UNFCCC) concept of "common but differentiated responsibilities" – meaning rich countries that emitted the most historically should do more to address the problem.

India last year proposed widening a deal on phasing down coal to include oil and gas. It won backing from more than 80 countries, but Saudi Arabia and other oil and gas producers blocked it.

Brazil has spearheaded negotiations on rules for carbon credit markets, through which it plans to monetise its vast forests.

South Africa secured a 2021 deal for $8.5 billion from the EU, United States and other nations to help its shift from coal to renewable energy. But the country now is facing its worst power crisis, with rolling blackouts and ageing coal plants frequently breaking down.

OTHER NEGOTIATING BLOCS:

G77 + CHINA

This alliance of 77 developing countries and China also holds that rich countries have a bigger responsibility to cut CO2 than poorer nations. A key question this year is whether the G77 will stick together as smaller climate-vulnerable nations seek urgent climate action, while larger members like China are wary of rapid CO2 cuts.

AFRICAN GROUP OF NEGOTIATORS

African countries will be pushing at COP28 for climate finance and financial mechanisms to speed up green energy projects.

Some African countries including Kenya, Ethiopia and Senegal have backed calls for phasing out fossil fuel production. But others like Mozambique want to develop their reserves of gas - both to boost their energy capacity and to capitalise on European gas demand. Any deal on phasing out fossil fuels, the group says, must allow poor nations to develop reserves in the short term to alleviate energy poverty.

ALLIANCE OF SMALL ISLAND STATES

The alliance, known by its acronym AOSIS, represents countries that are disproportionately vulnerable to climate effects including sea level rise.

The group's front-line experiences lend its members an influential position in COP talks, where its priorities include securing loss and damage finance and phasing out fossil fuel use to limit global warming to 1.5 Celsius - a threshold beyond which island nations face catastrophic climate impacts.

HIGH AMBITION COALITION

Chaired by the Marshall Islands and including Vanuatu, Costa Rica, the United States and the European Union, this group pushes for more ambitious emissions targets and policies - among them, this year, halting new coal plants and peaking the world's emissions before 2025.

LEAST DEVELOPED COUNTRY GROUP

This group's 46 nations are highly vulnerable to climate change but have contributed little to it. Aside from demanding that loss and damage be addressed, the LDCs want rich nations to double their financing for climate adaptation.

INDEPENDENT ALLIANCE OF LATIN AMERICA AND THE CARIBBEAN

The AILAC bloc is aligned with other developing countries in demanding greater climate ambition and more funding.