This team has been studying this marine region for almost 15 years, which is really important to understand change. These long-term studies are rare in Australia, which is why this is a very important study.

Rapid warming in several locations along Australia’s coasts is punctuated by extreme events - marine heatwaves. The study is very important as general warming and heatwaves in these fast-warming areas show what the future will look like.

This study shows the northern portion of the study region has now “permanently changed” – five years on from the marine heatwave of 2011 there has been no reversal to a past habitat. This marine change is the equivalent of a change from a “forest” to a “grassland” - and so the species that live in these regions have changed too.

We can expect more of these dramatic changes around Australia’s coasts in future.

Wernberg et al.’s new research documents an alarming change in another important habitat-forming, marine ecosystem – kelp forests. While the Great Barrier Reef (GBR) has received much recent media exposure in relation to the widespread coral bleaching event this past summer, the impacts of marine heat waves on other marine ecosystems, such as cool water kelps and seagrasses, are just as devastating.

Wernberg et al.’s study shows the Western Australian kelp forests have experienced a steady rise in water temperature over the past 30+ years, but that when this is also punctuated by a dramatic heat wave event (such as in summer 2010/2011 when sea surface temperatures were up to 5ºC warmer than usual), the response was a catastrophic die-off.

Clearly, the predominantly temperate kelps have reached their tipping point and are unable to respond and/or recover fast enough to outcompete the more tropical turf-forming seaweeds. The large temperate seagrass meadows in the World Heritage site at Shark Bay were also impacted by the same heat wave event, and recovery has been very slow.

This change in ecosystem has an immediate devastating impact locally, but more importantly documents what is likely to be a permanent retreat of the world’s temperate ecosystems.

This research by Wernberg et al. is an important warning of the effects of climate change on our coasts. Previous research in many marine ecosystems has shown that they can be changed into alternative stable states, and are then unlikely to recover.

The kelps along our coasts are important because they provide food and shelter for many animals. Kelp forests are some of the most productive marine habitats and are associated with important fisheries such as abalone and rock lobsters.

The plants protect themselves from being eaten with protective chemicals, but once removed, fast growing small seaweeds cover the rocks, and many tropical fish (such as parrotfish) and urchins feed on these. Small plants of the kelps are likely to be removed by these fish or urchins before they get large enough to be avoided due to their chemicals. Thus, it may be that the kelp forests that have been lost will never recover.

The seas on both our east and our west coasts have been warming and have experienced recent warm events. As warm tropical waters are far less productive than the colder temperate waters, we stand to lose many fisheries from the affected areas.