Even in this dangerous and unpredictable world, it's still possible sometimes to be surprised by hope - and on problems as challenging as the climate.

One morning recently I woke up to the news that Brazilian President Jair Bolsonaro had ordered the Brazilian army to tackle the fires blazing through Amazonia. Later that day news came that Russia is planning to ratify the Paris Agreement on Climate Change. That was a hopeful day - to start with, at least.

There is still time to tackle climate change, but it's going to need an unprecedented effort from us all. Global greenhouse emissions are reaching record levels, with no sign of peaking, and sea levels are rising. The last four years were the hottest on record, and arctic winter temperatures have risen by 3 C since 1990. We are now seeing the impact of climate change on health through air pollution, heat waves and risks to food security.

But hold on to hope. The latest analysis shows that if we act now, we can reduce carbon emissions within 12 years and limit the global average temperature increase to well below 2 C and even to just 1.5 C above preindustrial levels, as the Paris Agreement requires. But that can succeed only with ambitious action, and so far the world has not shown anywhere near the ambition needed.

To raise ambition and speed up action on implementing the Paris Agreement, UN Secretary-General Antonio Guterres will host the 2019 Climate Action Summit on Sept 23. It aims to demonstrate not only a surge in countries' political ambitions, but a massive movement in the global economy as well, to make it possible to achieve the objectives of the Paris Agreement and the UN's Sustainable Development Goals.

And it is aiming to result in much faster action.

So governments are being asked not just to make elegant speeches in New York, but to present concrete, realistic plans. These should list out how they will realistically improve their commitments under the Paris Agreement (known as their Nationally Determined Contributions - the emissions cuts they intend to make) by 2020, and then actually reduce those emissions by 45 percent over the next decade, and to net zero by 2050.

It sounds simple; it almost certainly won't be. The UN says it will involve transformative changes in the areas of energy transition, infrastructure, cities and local action, industry transition, resilience and adaptation, nature-based solutions, climate finance and carbon pricing.

And New York 2019 will also have to spell out how to achieve a full transformation of economies in line with the goals, not creating winners and losers or adding to economic inequality. And it needs also to include women as key decisionmakers.

It will focus on finding how to move the world to renewable energy, sustainable and resilient infrastructures and cities relying on mass transport and caring for the urban poor, sustainable agriculture and management of forests and oceans, resilience and adaptation to climate impacts, and aligning public and private finance with a net zero economy.

Doing all this should be easy, and in one sense it is. Business is recognizing the advantages to be gained from moving to a net-zero society. Accelerated climate solutions can strengthen economies and create jobs, while bringing cleaner air, preserving natural habitats and biodiversity, and protecting the environment.

New technologies and engineering solutions are already generating energy more cheaply than fossil fuels. Solar and onshore wind are now the least expensive sources of new bulk power in virtually all major economies. But there's much more to do to overcome the inertia and resistance to change that continues to heat up the world.

That's going to mean, for example, ending subsidies for fossil fuels and agriculture that comes with high emissions, shifting instead toward renewable energy, electric vehicles and climate-smart practices. It means carbon pricing that reflects the true cost of emissions, from climate risk to health hazards. And it means faster closure of coal plants, ending the construction of new ones and replacing dirty jobs with healthier alternatives.

There are grounds for hope, but there are plenty of reasons for concern. Yes, there are national and global efforts to extinguish the Amazonian fires. But how much damage have they done already which can never be put right? Scientists warn that Brazil could be nearing the point where its forests will start drying out - and be damaged beyond saving. Yes, probably Russia will soon ratify the Paris Agreement - but so what? What if the agreement is still too weak to cut carbon emissions deeply enough? Time is running out very fast.

A wise man once told me: "Protecting the environment means finding new ways to think." How fast can we do that?

The author was a veteran BBC environment journalist. After his retirement, he trained journalists in developing countries to help them improve environment and climate change news coverage. He authored Kick the Habit: A UN Guide to Climate Neutrality.

The author contributed this article to China Watch exclusively. The views expressed do not necessarily reflect those of China Watch.

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