The Great Barrier Reef is one of the most vibrant habitats. A forest of coral that covers the same area as Italy and is home to 10% of all the fish species in the ocean, it shimmers with colours.

But the reef has lost its sheen. Greens and yellows are fading to grey. Warming waters have disrupted the symbiosisDespite being rooted to the seabed, coral itself is in fact made up of animals. These animals secrete chemicals that form a rock-like structure, which provides a home for algae. The algae in turn help the coral by removing waste and producing food through photosynthesis. When species live together for mutual benefit in this way, it is called symbiosis. that allows reefs to thrive.

This is mass bleaching. Before 2016 only two events had been observed in the Great Barrier Reef. Since then there have been four.

Bleaching is not fatal as long as the coral can recover. But thanks to global warming, recovery time is scarce. "The reef is about 1.5 degrees centigrade warmer than it was 150 years ago," says the chief scientist at the Great Barrier Reef. "Unexpected events are now to be expected."

Yet amid the gloom there is hope. On the same day as news of this bleaching emerged, so did a story of the revival of Britain's wetlandsA landscape that is always or often flooded with water. This sort of environment can be home to particularly rich and diverse ecosystems and especially a wide range of birds. and the return of a beloved bird.

Bitterns - small herons with a unique call - were hunted to extinction in the UK by 1870. In 1990 efforts to reintroduce them seemed to be failing, with just 11 known males. Now a survey has found 228.

A scientist from the RSPBThe Royal Society for the Protection of Birds, founded in 1889, is Britain's largest conservation charity. said that this is "probably the biggest conservation success story of the last 40 years".

Could coral reefs bounce back? It's possible. Some reefs have proved resilient. Scientists are developing new techniques to help them endure, such as recruiting tourists to replenish dead corals through "coral gardeningThis fiddly process involves breeding coral in controlled environments and then inputting them into areas where coral has been damaged or killed.".

Larger trends are emerging that hint at potential salvation from catastrophe.

Solar energyEnergy from the sun, which can be captured by solar panels and used to produce electricity., once plagued by inefficiency, is proving effective. Solar power costs less than experts predicted it would by 2050 and its usage is growing exponentiallyExponential growth is when the rate of growth increases steadily over time, for instance by doubling: 1, 2, 4, 8 rather than 1, 2, 3, 4. This kind of growth has the capacity to lead to dramatic changes over relatively short time spans.. If this continues, we could end our reliance on fossil fuelsFuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming. soon.

This is not the only transformative green innovation. High-tech farming methods could soon free up swathes of land, while electronic vehicles could make transport carbon-free.

These developments are highlighted in a recent think-tankAn organisation that conducts research in order to produce policy recommendations for governments and other large organisations. The think-tank behind this report was RethinkX. report whose authors believe that "conventional thinking" about climate is beset by pessimism and error.

"By supporting clean... energy, transportation and food," the report suggests, we can "reach net zero emissions before 2040 and lay the groundwork for a complete solution to climate change".

Yes: We have the tools to save the world; the only obstacle is our own failure of imagination and will. If we fight climate change with the same urgency as we fight wars, it is a battle we can win.

No: We must confront the grim reality: climate change is already having disastrous effects, and it's going to get worse. All we can hope for is to minimise the damage.

Or... Humanity is now the major force shaping our planet, and that is not going to change. We need to stop thinking about climate change as a one-off crisis and accept that we will be dealing with it for as long as our species exists.

Symbiosis - Despite being rooted to the seabed, coral itself is in fact made up of animals. These animals secrete chemicals that form a rock-like structure, which provides a home for algae. The algae in turn help the coral by removing waste and producing food through photosynthesis. When species live together for mutual benefit in this way, it is called symbiosis.

Wetlands - A landscape that is always or often flooded with water. This sort of environment can be home to particularly rich and diverse ecosystems and especially a wide range of birds.

RSPB - The Royal Society for the Protection of Birds, founded in 1889, is Britain's largest conservation charity.

Coral gardening - This fiddly process involves breeding coral in controlled environments and then inputting them into areas where coral has been damaged or killed.

Solar energy - Energy from the sun, which can be captured by solar panels and used to produce electricity.

Exponentially - Exponential growth is when the rate of growth increases steadily over time, for instance by doubling: 1, 2, 4, 8 rather than 1, 2, 3, 4. This kind of growth has the capacity to lead to dramatic changes over relatively short time spans.

Fossil fuels - Fuels made from decomposing plants and animals, including coal, natural gas and oil. These fuels release carbon dioxide, causing global warming.

Think-tank - An organisation that conducts research in order to produce policy recommendations for governments and other large organisations. The think-tank behind this report was RethinkX.