Two chambers of the Earth's green heart. Professor White describes the Amazon and the Congo Basin as the two linked chambers of the planet's beating heart rather than its lungs. The Amazon pumps water into the atmosphere that affects rainfall as far away as California, while the Congo Basin sends water toward the Blue Nile, Ethiopia, Egypt, Angola, and even the Okavango Delta.

What a tree-lined street can teach us. He thinks of cities as mini planets. A tree-lined street can be ten to fifteen degrees centigrade cooler than one without trees, and children with access to green spaces have fewer health problems. Scale that up, and the world's great rainforests are the central parks of our planet.

Why science and funding go together. He calls earth scientists people with a crystal ball. Losing the Congo Basin forest, he warns, could displace many millions of people who depend on its water, and he offers rough, approximate figures for the Horn of Africa, Egypt and the Sahel. Protecting the forest, he argues, is also protecting economies and stability.

Flying rivers and the value of a forest. In the Amazon, where thousands of scientists have gathered good data, the moisture carried by "flying rivers" is estimated to support about 20 billion US dollars of agriculture every year. The Congo Basin has been far less studied, so we know much less about what it is worth.

The science gap. Decades ago, governments, USAID and foundations such as the Gordon and Betty Moore Foundation invested heavily in building Amazon science. That never happened in the Congo Basin, where the Science Panel could find only about 120 publishing scientists when it began.

Parks, leadership and a hopeful outlook. From Yellowstone to Virunga, parks have long been a conservation tool, and he sees strong leadership today from African heads of state and from China, where he visited an operations room creating thirty-six new national parks. He calls himself a died-in-the-wool optimist.

From slash-and-burn to modern tropical farming. In the Democratic Republic of Congo, much deforestation comes from poor rural farmers using slash-and-burn methods that date back about 2,600 years. Investing in modern tropical agriculture, which can be up to 20 times more productive, along with protected areas, could ease the pressure on the forest.

The most miraculous invention on the planet. Trees cool our cities, store and purify water, create rainfall, and turn carbon dioxide into wood. He calls for a global alliance with trees, planted strategically, such as upwind of farmland, and points to tree-planting efforts across the Sahel and in China.

Where the money needs to go. Beyond science, he points to national parks, well-managed ecotourism that makes a lion or an elephant worth more alive than dead, and long-term funding to look after protected areas once they are built.

Lessons from Scotland's deer. After wolves, bears and lynx disappeared from Scotland, deer numbers soared, blocking forest regrowth and contributing to Lyme disease. He explains why carefully monitored culling can help restore balance, and why many Scottish vegetarians eat venison.

Healthy forests and human health. Where biodiversity is greatest, diseases are too, and healthy ecosystems keep them in their animal reservoirs. He cites Ebola and the origins of HIV as warnings that destroying ecosystems is like opening a Pandora's box.

What each of us can do. Eat a seasonal, local diet, plant trees if you have a garden, and speak up for green spaces in local politics. He also shares tales of foraging at the Old Course in St Andrews, an organic golf course where herbs go into a local golf gin, and recommends the book Entangled Life by Merlin Sheldrake on trees and fungi.

Tipping points and the "wise ape." Citing scientist Johan Rockström's work on planetary tipping points, he explains why the pace of change matters. Balancing development and nature is not technically difficult, he says, but it is hard politically and economically, and it is time we earned the name Homo sapiens.