The world's oceans are warming. A loss of coral reefs as a result is having a devastating impact on global fish stocks, while warmer waters have the potential to spread disease.

It is these and a diverse range of other environmental challenges that around 6,000 delegates from 170 countries are discussing as part of the International Union for the Conservation of Nature's (IUCN) World Conservation Congress.

And the world's environmental problems are pressing. “Planet at the crossroads” is the motto of this year's congress, and it comes at an important time for nature, says IUCN general director Inger Andersen. “No IUCN Congress before has come at a more pivotal time for humanity's relationship with the environment.”

Environmental experts taking part in the ten-day congress face a formidable task. With a comprehensive program, they must decide on an IUCN plan of action that will lead the way for global environmental protection over the next four years.

“The broad agenda shows us the diverse ways in which the threat to biodiversity will affect us and the environment,” explains Barbara Maas, species protection expert at German conservation organization NABU. “The delegates are faced with a daunting task that can only be solved through courageous conservation measures.”

Leading the way for conservation

The IUCN was founded in 1948 and is the world's largest environmental protection organization. Its 1,000 members include both governments and non-governmental organizations.

The conservation union also holds considerable weight at an international level. It publishes a list of endangered animals and plants, is committed to the expansion of nature reserves on the continents and in the oceans, it seeks to strengthen global environment legislation, advises the UNESCO World Heritage Committee, contributes to the World Climate Report and helps to design international agreements.

Every four years, the IUCN invites delegates from across the globe for the World Conservation Conference. Last time, it was held in South Korea, this year it is taking place on the Pacific island chain of Hawaii, which belongs to the United States.

Among the issues being discussed, delegates will also prepare the Convention on Biological Diversity in Mexico and the CITES conference in South Africa, which will focus on regulation of international trade of endangered plants and animals. “The IUCN must give an important signal with regards to better protection of the African elephant,” said Maas. “Every year, around 35,000 fall victim to poaching. But pangolins, lions, sharks and rays also need more effective protection measures.”

IUCN aims to preserve the diversity of nature and calls for environmentally sustainable use of resources. Currently, the main causes of biodiversity loss are mainly deforestation and agriculture. With support from international and national conservation and reforestation programs and the expansion of protected areas, the IUCN is trying to counteract those causes.

Hidden challenges

Climate change is now also a huge challenge for conservation. According to a recent IUCN study, the world's oceans are getting warmer, a factor that is increasingly impacting the marine ecosystem.

“Ocean warming is one of this generation's greatest hidden challenges – and one for which we are completely unprepared,” said IUCN's Andersen. “The only way to preserve the rich diversity of marine life, and to safeguard the protection and resources the ocean provides us with, is to cut greenhouse gas emissions rapidly and substantially.”

According to the study, ocean warming has already led to a reduction in numbers of particular species of fish in East Africa and the western Indian Ocean as a result of the loss of coral.

And if global greenhouse gases are not reduced, the forecast for South-East Asia is that fish stocks – and with them the associated fishery catches - will plummet by 10 to 30 percent in 2050, compared with 1970 to 2000.

It is also feared that ocean warming could also increase disease in the population. Pathogens and bacteria spread more easily in warmer waters. Ocean warming also leads to changes in the weather: the number of severe hurricanes has increased by some 25 to 30 percent per degree of warming, according to the study.

In addition, there has been an increase in wet weather in the mid-latitude regions and monsoon areas and less rain in some subtropical regions. This could have a significant impact on crop yields, for example in North America and India, said the report.

The authors of the study suggest that the oceans are important for humanity. They recommend that the effects of ocean warming should be investigated further and marine protected areas expanded. Greenhouse gas emissions should also be quickly curtailed.