Iliana Baums, Professor of Marine Conservation, fears negative consequences of climate change for coral reefs, but also sees encouraging new approaches for saving the reefs.

"Coral reef ecosystems are threatened by increasing sea temperatures. When the water gets too warm, the symbiotic relationship between the coral host and its single-celled algal symbionts breaks down. The algal cells separate from the host tissue, leaving behind only the translucent animal tissue. Through it, you can see the white calcium carbonate skeleton. This process is known as coral bleaching. Especially in the Caribbean, we have seen the consequences of this in the form of mass bleaching events and really extensive coral death. 

Bleaching events are becoming increasingly frequent, and more and more of the coral animals die. As these events become increasingly frequent, more and more corals are dying. They don't have much energy left over to defend themselves against infectious diseases or to produce offspring. This is a serious issue because coral reefs are particularly species-rich habitats that protect coasts during storms.

So, what can we do? In general, animals can adapt quite rapidly to changing conditions. The process of natural selection involves the differential survival of animals with better characteristics; in this case, those with higher temperature tolerance. However, there is a lot of chance involved. There is no guarantee that the selection process will work in time to prevent extinction. This is where humans can intervene. The most critical thing we can do is to limit global warming. There's just no way around it. Nevertheless, we must also accept that we are already on a trajectory of substantial warming. Therefore, we must take action to help corals survive these rapid changes in the hope that warming will slow down and conditions will stabilise.

As coral researchers, our approach is to preserve as much genetic diversity as possible, for example by building biobanks or by cryopreserving some of the eggs and sperm. We can make reproduction possible between coral colonies that are too far apart for it to occur naturally. By doing this, we can assist the corals to undergo natural adaptive processes, thereby maintaining diversity and ensuring that they continue to reproduce.

One of the major obstacles we currently face is the legal framework that regulates the exchange of endangered species and genetic materials. These permitting processes are very time-consuming and cumbersome. Given the rapid and catastrophic events we are experiencing, we urgently need regulatory reforms to support our mission to preserve coral diversity.

However, what gives me hope is the incredible innovation and energy that so many people are contributing to tackling the crisis. Significant technological progress has been made over the past ten years, such as cryopreservation and reproducing corals in captivity, which was very challenging for a long time. We now have a better understanding of how to settle corals, which substrates they need to survive and how to help young animals survive. A lot has changed. However, given the vast size of the Caribbean and the Great Barrier Reef alone, it is a real challenge to restore reefs globally to their current state."