Image source, Florian Plaucheur/AFP via Getty ImagesImage caption, El Niño brought intense flooding and landslides to southern Brazil in 2024ByEsme Stallardsenior climate and science reporterMark Poynting and Becky DaleBBC Verify and Yvette Tan, Tiffanie Turnbull and Nikita YadavThe world has entered a "danger zone of extreme weather" as the impacts of El Niño start to be felt globally, UN head António Guterres has warned.The World Meteorological Organization (WMO) has released the latest data on the natural weather phenomenon showing it could be the strongest for more than 70 years and last until at least February 2027.El Niño changes weather patterns around the world, pushing some regions into drought whilst others experience stronger typhoons and flooding.Forecasters also say El Niño will boost temperatures in some places, coming on top of rising heat globally from human-induced climate change."El Niño is being supersized before our eyes. The science leaves no room for doubt: the planet is in uncharted waters, and those waters are heating up," Guterres said.The BBC spoke with governments and scientists about the measures being taken globally to reduce the risk of deaths, displacement and environmental damage. Early warning systems have been strengthened and deployment of pre-emptive medical assistance, but the strength of this particular event has raised serious concerns particularly for vulnerable groups.The WMO - a UN agency - said it has undertaken a "major mobilisation" to try to circulate its forecasts of potential extreme weather events, linked to El Niño, to as many communities as possible.WMO Secretary-General Celeste Saulo warned: "El Niño has the potential to deliver a massive blow to communities and economies across the world."El Niño is a natural weather phenomenon that develops in the Pacific Ocean and is linked to a change in wind patterns. It allows warm water to spread eastwards and releases heat into the atmosphere.Sea temperatures in the central and eastern tropical Pacific have risen sharply in recent months - a clear sign of a strengthening El Niño.In the Pacific's key monitoring region, surface temperatures have been well over 2C above average in recent weeks, putting it on track to be declared a "very strong" event.But it is expected to surpass even that marker. Monthly sea surface temperatures could get close to 4C above average, forecasts suggest.This would make it the strongest El Niño since at least 1950, by potentially a large margin.Temperatures are even more exceptional below the surface of the Pacific - in places more than 8C above average.Above-normal sea temperatures are also expected in other parts of the world including the Indian Ocean, tropical Atlantic and around parts of the Australian coast.With its rich marine life, changes in ocean heat are of particular concern to Australia.It has been plagued by marine heatwaves in recent years - driven by climate change. El Niño is a natural phenomenon, but it tends to bring the kind of extreme heat which also drives those disasters, Dr Alistair Hobday, chief researcher at Australia's science agency, told the BBC.This year, marine heatwave forecasts indicate the Great Barrier Reef will be spared the worst of the conditions, giving coral there more time to recover."[But] Southern Australia is getting slammed," said Hobday.Last time a marine heatwave hit South Australia and Tasmania, there were starving penguins, fish kills, suffocating algae outbreaks, and jellyfish invasions.Australia has recently introduced early warning systems for marine crises - this gives time for financial relief for fisheries to be established, relocation of crucial species and increased coral monitoring.But this event is shaping up to be unprecedented - and Hobday admits he is quite worried.Reduced rainfall brings drought and trade disruptionWhile the impacts on global weather are likely to be felt well into 2027, the WMO expects significant changes in rainfall patterns over the next few months.Drier-than-usual conditions are forecast across large areas of South East Asia, Central America and northern parts of South America, increasing the risk of droughts and wildfires.On Thursday, the number of vessels passing through the Panama Canal will be reduced by more than 10% in anticipation of lower rainfall.About 14,000 ships per year use the artificial waterway - as well as being a crucial route for global trade, it is also a key source of income for Panama, bringing in about $3bn (£2.2bn) a year.Indonesia is racing to contain wildfires that have burned more than 107,000 hectares of land nationwide this dry season. Like some other parts of South East Asia, it is facing a longer season this year.A resident in Central Kalimantan told BBC News Indonesia he had been experiencing wildfires "for more than a month"."The smoke has become quite thick. When we step outside, our eyes start to sting. The smell of the smoke is also quite strong," said Darwin Romy.Authorities have said they are deploying cloud-seeding aircraft to trigger rains to extinguish these fires, and its government has promised resources to contain the fire and arrested dozens over allegations of using it to clear land.Image source, Monirul Bhuiyan/AFP via Getty ImagesImage caption, Countries in Southern Africa, like Botswana, experienced severe drought during the last El Niño eventStronger typhoons and landslide riskThousands of miles away, China is expecting seven typhoons to make landfall in this year alone – something the country's experts have said is linked to the effects of a super El Niño.In July alone, China experienced three typhoons - Bavi, Noul and Maysak - which left dozens dead.And in August, more than 1m people were forced to evacuate their homes as Typhoon Dolphin hit – bringing heavy rains and strong winds.Similarly, wetter-than-average weather is expected in parts of eastern Africa, southern Brazil and the southern US, raising the chances of flooding."We are already seeing disruption and devastation from droughts and floods and we expect these impacts to increase as El Niño intensifies," said Prof Celeste Saulo, secretary general of the WMO.This is all happening on top of long-term human-caused warming, making the impacts potentially more intense. Some scientists believe climate change could even be making El Niño events stronger, but this is not yet certain.Peru is particularly vulnerable to El Niño, as its coastline borders the eastern Pacific.Parts of the country, along with Ecuador and parts of Brazil, have previously experienced increased rainfall, resulting in flash flooding and landslides, particularly in urban centres where the water is less able to drain away.Miguel Aréstegui, climate resilience lead at Practical Action, which helps countries prepare for extreme weather, said "we are significantly concerned, but that concern needs to translate into preparedness rather than alarm."He said Practical Action had been working with partners over recent years to make sure the public had better access to early warning systems, including sharing information on river levels, flood risks and weather forecasts.At the end of last month, the US announced it was deploying the vessel USNS Comfort to the Peruvian coast to provide additional medical assistance and technical equipment for when El Niño reaches its peak.However, Aréstegui said El Niño "does not arrive in a vacuum". There are bigger, structural issues that make these events worse and which take much longer to resolve such as "housing in exposed areas, fragile water and sanitation systems, and a weak healthcare system", he said.