World leaders are meeting to discuss tackling climate change at a big UN summit in Dubai.
It follows a year of extreme weather events in which many climate records have been broken.
COP28 is the 28th annual United Nations (UN) climate meeting where governments will discuss how to limit and prepare for future climate change.
The summit is being held in Dubai, in the United Arab Emirates (UAE), from 30 November until 12 December 2023.
COP stands for "Conference of the Parties", where the "parties" are the countries that signed up to the original UN climate agreement in 1992.
The UAE is one of the world's top 10 oil-producing nations.
It has appointed the chief executive of the state-owned oil company, Sultan al-Jaber, president of the COP28 talks.
Oil - like gas and coal - is a fossil fuel. These are the main causes of climate change because they release planet-warming greenhouse gases like carbon dioxide when burned for energy.
Mr Jaber's oil company plans to expand production capacity.
Documents leaked to the BBC suggest the UAE planned to use its role as host to strike oil and gas deals.
Mr Jaber has previously argued that he is uniquely well-placed to push for action from the oil and gas industry, and that as chairman of renewable energy firm Masdar, he has also overseen the expansion of clean technologies like wind and solar power.
It is hoped COP28 will help keep alive the goal of limiting long-term global temperature rises to 1.5C. This was agreed by nearly 200 countries in Paris in 2015.
The 1.5C target is crucial to avoid the most damaging impacts of climate change, according to the UN's climate body, the Intergovernmental Panel on Climate Change (IPCC).
Long-term warming currently stands at about 1.1C or 1.2C compared with pre-industrial times - the period before humans started burning fossil fuels at scale.
As a result, the window for keeping the 1.5C limit in reach is "rapidly narrowing", the UN says.
As well as progress towards the existing Paris goals, COP28 will concentrate on:
There will also be themed days on issues including health, finance, food and nature.
Around 200 governments have been invited.
US President Joe Biden and China's Xi Jinping are not expected to attend, but both countries will be represented.
Pope Francis has cancelled his planned visit due to illness.
Environmental charities, community groups, think tanks, businesses and faith groups will also take part.
Hundreds of delegates with links to fossil fuels attended COP27 in 2022.
There is likely to be disagreement about the future of "unabated" fossil fuels - coal, oil and gas which are burned without technologies to capture their emissions.
Mr Jaber has called for a "phase down" in their use, meaning a reduction over time, but not a complete end. However, the EU and other groups are expected to push for a full "phase out".
Climate campaigners point out that restricting agreements to "unabated" fossil fuels would allow some production to continue. They say there is no guarantee capturing emissions will work at scale.
There are already far more fossil fuels currently being produced or under construction than could be burned if the world is to limit warming to 1.5C, according to a recent report by the UN Environment Programme.
The fund was agreed at COP27. The idea is that richer countries will pay poorer countries already facing the effects of climate change - because richer countries have contributed most to global warming.
But the details of how it will work have remained deeply contested, with richer countries like the US reluctant to accept liability for past emissions.
While a relatively small amount of money was pledged on the opening day of COP28, getting the fund up and going is seen as a crucial step in building trust between richer and poorer countries.
Separately, in 2009, developed countries pledged to give $100bn (£82bn) a year to developing countries by 2020, to help them reduce emissions and prepare for climate change.
Critics of previous COPs, including campaigner Greta Thunberg, accuse the summits of "greenwashing" - where countries and businesses promote their climate credentials without making the changes needed.
But as world leaders gather, the summits offer the potential for global agreements that go beyond national measures.
For example, the 1.5C warming limit, agreed in Paris at COP21, has driven "near-universal climate action", according to the UN.
This has helped bring down the level of warming the world can expect - even though the world is still not acting at anywhere near the pace needed to achieve the Paris goals.