Last week's flurry of terrifying climate reports demands a stronger response - the next two weeks in Bonn must point the way to the next climate crunch point

The pre-COP release of genuinely terrifying studies on the scale of the climate challenge is now a well-established part of the choreography for the UN's annual exercise in existential planetary crisis management. And yet, last week's burst of reports still had the power to shock.

The outlook, as confirmed by the World Meteorological Oranisation, UN Environment Programme, PwC and others is, how can we put this? Disappointing? Decidedly sub-optimal? Devastatingly bleak? Delete as appropriate to your level of 'climate optimism'.

The conclusions will have been familiar to anyone who works in sustainability, but they bear repeating. Greenhouse gas emissions are at their highest atmospheric concentrations in at least 800,000 years, and probably much longer. Scientists have identified a spike in methane emissions they cannot fully explain, fueling fears warming feedback loops could be underway. The Lancet reports climate impacts and air pollution are already damaging the health of millions of people globally. The Guardian calculates numerous coastal cities are on track to be inundated by rising sea levels this century. Senior US military and security experts reckon climate change will 'create the world's biggest refugee crisis' - it is hard to argue with them.

'Climate sceptics' can debate all they like about what impact record concentrations of greenhouse gases will have on worldwide temperatures; what they cannot dispute is we are conducting a potentially irreversible experiment on the climatic conditions that made human civilisation possible.

Meanwhile, the impressive progress the green economy has made - and it is hugely impressive - is dwarfed by the scale of decarbonisation required. As PwC noted the world's top economies are now cutting their carbon intensity by 2.6 per cent a year, which sounds great until you realise they need to be cutting carbon intensity 6.3 per cent a year. Losing 4-1 is better than losing 4-0, but it's still pretty terrible.

The UN Environment Programme (UNEP) puts it another way - the 'emissions gap' between the pledges made by countries through to 2030 and a credible 2C scenario stands at between 11 and 13.5 gigatonnes of carbon dioxide equivalent. If that sounds like a lot, it is because it is. All the emissions reductions pledges made by cities, regional governments, and the private sector amount to just a couple of gigatonnes. Meanwhile, the current pipeline of coal power projects could add another 150 gigatonnes over their lifetime. The report also assumes countries make good on the often conditional climate pledges that have made. Any Trumpian backsliding will only widen the gap. Oh, and you heard global low carbon investment actually fell last year, right?

These reports and their klaxon-like warnings should have dominated front pages and news bulletins around the world - that they didn't is distressingly informative.

Thankfully, there are enough causes for optimism to stop this month's UN summit feeling like an exercise in futility. As PwC notes the UK and China did reduce their carbon intensity by more than the 6.3 per cent benchmark last year. Deep decarbonisation is both possible and compatible with continued economic progress. UNEP reckons technologies and measures that have "modest or net negative costs" could cut emissions by up to 22 gigatonnes in 2030. The emissions gap can be closed. Clean energy investment has stalled because renewables costs have plummeted, not because deployment is slowing.

In fact, the International Finance Corporation provided the one major bright spot last week with a report arguing the $1tr already invested in climate action could bring the Paris Agreement's goals within reach. When those notorious eco-hippies at the World Bank thinks the economic equation in favour of bold climate action is self-evident then there are reasons for hope.

And yet none of this can distract from the alarm bells being rung by the climate scientists, the WMO, UNEP, and the lived experience of anyone who can see where the glaciers used to be.

These warnings contain three crucially important lessons for political and business leaders as they gather in Bonn tomorrow - all three of them must be heeded.

The first lesson is the most obvious. There is simply no time for further delay. Every policy lever, every investment plan, every available R&D dollar, every sinew, needs to be strained in pursuit of deep and rapid emissions reductions. The urgency which was sparked by the Paris Agreement and which manifested itself a few months ago in the raft of new climate pledges made by corporate giants at New York's Climate Week now needs to be amplified and expanded.

The temptation over the next few weeks will be to turn the UN climate summit into another plot line in President Trump's personal psychodrama; to make everything about his narcissistic dismissal of all basic principles of scientific inquiry and risk management. This would be a mistake. Governments and businesses must push back hard against Trump's reckless sophistry, but they must also ensure they deliver on what they can control.

To that end there has to be tangible new funding commitments from industrialised nations that allay any fears the Paris Agreement pledge to mobilise $100bn a year of climate funding from 2020 could be compromised. National governments also need to send an explicit signal they are aware of the emissions gap and will respond with renewed policies and investments that will deliver deep decarbonisation by 2030. There needs to be an unequivocal understanding that programmes such as the UK's new Clean Growth Strategy are a starting point, not a destination.

This action needs to be emulated and then surpassed by the corporate sector. More firms need to come forward with public science-based targets and clean energy pledges. But beyond that, they also need to drive industry-wide progress.

I was speaking to a head of sustainability at a FTSE300 firm last week who was quietly astonished at the vast array of 'low hanging fruit' that was available across their sector. Their company had a punchy science-based target for 2030 and some bold green investment plans, but throughout much of their industry simple, negative-cost emissions reduction efforts still go ignored. The prime example for multiple sectors remains LED lighting, where sizeable returns on investment are available within 18 months to two years, and yet countless companies continue to throw money away by deferring upgrades. Plenty of other examples abound and they will only become more numerous as the cost of renewables, energy storage and electric vehicles continues to plummet. These market failures, this flawed management, needs fixing - and fast.

There will be plenty of debate over the next two weeks in Bonn about how to overcome the barriers to deep decarbonisation. Is 100 per cent renewables possible? Do we need CCS? How do we tackle 'hard to abate' industries? What role with negative emissions technologies have to play? How do we transform land use? All these debates are critically important and must continue, but they cannot distract from the simple actions that must be taken now to deliver instant emissions cuts.

Governments and businesses should engage in long term thinking, but they also need to immediately deliver the policies and programmes we know work: the energy efficiency upgrades, the standards and rules-based policies, the clean energy auctions, and coal phase outs. It's not glamorous, it's not going to win anyone a Nobel Prize, but it is the only way to close the emissions gap and keep us on a path that then makes deep decarbonisation possible. It's time to just get on with it.

The second lesson is also obvious, but remains the subject of a psychologically comforting, but ultimately damaging, omertà. We need to start talking about climate adaptation and resilience. This is not defeatism, it is realism.

Businesses, investors, and policymakers all need to take the warming that is likely already baked in to the climate system much more seriously. Any large business or infrastructure project that is not fully engaged with the risks presented by rising sea levels and changing weather patterns needs to rectify this blatant failure sharpish. Investors and regulators need to start asking hard questions. The fossil fuel assets that will hopefully be left stranded by the low carbon transition could be dwarfed by the real estate and infrastructure assets that could be left literally stranded by the tides.

The final lesson is one for business leaders and corporate planners everywhere. Even before the champagne corks were cleared up after the Paris Agreement was gavelled through attention was already turning to the next big international climate summit, the next chance to engineer a global political moment in pursuit of bolder action. That point will almost certainly come in 2020 and the primary goal of this week's gathering in Bonn, beyond wresting some welcome new pledges from leading economies, is to light the path to the next crunch meeting.

The start of the next decade is likely to prove critical for technical, environmental, economic, and political reasons. It is then the Paris Agreement formally comes into full effect and it is then the first wave of updates to national climate action plans, or NDCs in the jargon, should start to gather pace. It is then that provides the last credible point to close the emissions gap and keep the 2C target within reach. It is then that stalled global emissions levels need to start to rapidly fall. It is then that renewables' cost competitiveness can be expected to become unequivocal and electric vehicles can expect to start to challenge their conventional rivals on price. And it is then that President Trump (or perhaps Pence) might just be turfed out of office.

When all that happens, expect a global step change in the pace of decarbonisation and the political and public support for sweeping climate action. Support for renewables already stands at 70 per cent to 80 per cent in the UK, imagine what will happen when climate impacts become even more visible?

Action to curb emissions cannot be delayed. It must come now. But as anyone who has ever procrastinated (i.e. everyone) knows, humans benefit from deadlines, they appreciate and understand the appeal of history-turning moments.

There is an outside chance it could come sooner, but 2020 is likely to be the next such point and all companies need to be planning now for the political battles that will come and the fresh wave of climate action that should follow. Because without such a tipping point, without the moment when the Paris Agreement's aspiration becomes a full spectrum economic reality, the autumn tradition of ignoring credible warnings of climate catastrophe will only be retired when the catastrophic outcomes they predicted unfold - and perhaps not even then.