Our living planet is in peril and so is humanity. To those who say this is alarmist speak and who have called the striking school children truants, we reply that these young people are correct to raise the alarm and their concerns and fears are entirely justified.
When Antonio Guterres, Secretary General of the United Nations described the recently published IPCC 1.5oC report  as an “ear-splitting wake up call to the world”, it is clear that young people heard him, even if world leaders apparently did not. An international consensus of copious scientific evidence clearly demonstrates the importance of limiting global temperature rise as close to 1.5oC as possible and the extreme urgency for transformative action at all levels.
As doctors we understand that in order to successfully manage any emergency, the first step is to identify that that is the situation we find ourselves in.
“Society’s activities have pushed climate change, biodiversity loss, shifts in nutrient cycles (nitrogen and phosphorus), and land use beyond the planetary boundaries into unprecedented territory.” - J Rockstrom 
To use the human body as an analogy: damage to one organ or physiological system is obviously a threat to an individual’s health and even life: the greater the extent of stress or damage, the higher the risk. Multiple organs stressed or failing at the same time, can lead to a cascade of events, leading to sudden and rapid deteriorations and ultimately potential loss of life. Planetary life support systems are similarly highly interconnected and show feedbacks and trigger thresholds. Ongoing damage to our planet’s climate, oceans, forests, species and other systems, presents an existential threat to life on Earth as we know it.
As described by Professor James Hansen: “The climate system is now out of equilibrium. Amplifying feedbacks [are] of great concern. There is real, imminent danger that we will hand young people and future generations a climate system that is practically out of their control.” He goes on to describe our current predicament as a “planetary emergency”. 
The Lancet Commission describes climate change as “the greatest public health threat this century” .
Health impacts and risks are multiple and varied and may be directly caused by climate change as well as indirectly. As well as their futures being put at stake, children are among the groups most vulnerable to climate health risks and currently make up approximately 80% of deaths from climate change . They are also more vulnerable to serious health impacts from environmental pollution, including air pollution .
The Lancet Commission has identified that it is lack of political will which is the greatest barrier to necessary climate action: yet many of these same actions provide “probably the greatest public health opportunity this century”. Climate action, including addressing our food, energy and transport systems, could reap enormous rewards for children’s and others’ health now, addressing conditions such as malnutrition, obesity and asthma to name but three examples.
Climate change is also a justice issue: social, racial, gender and intergenerational. The people and communities on the front line from climate impacts have done the least to contribute to it. The medical profession has a long history of promoting change for social justice and public health issues and holds a privileged and trusted position in society. A key message of the 2018 Lancet Countdown report is that health professionals around the world are increasingly responding to the growing health challenge posed by climate change . We believe it is now necessary for more of us to do so.
Both February and April of this year saw Ashdown Forest in the UK burning: the setting for A.A. Milne’s Winnie the Pooh stories . Watching this, as well as the brave but understandably fearful children sacrificing their education, it appears we are stealing from these young people in multiple ways: including education, their sense of safety, critical aspects of their childhoods, their health and their futures. Children are taking action because the adults charged to protect them and their futures have collectively failed to do so. They are children. They cannot and should not have to bear this burden alone.
“Young people like Greta Thunberg have understood the climate challenge humanity is facing MUCH better than many political leaders. They deserve support and respect.” - Prof. J P van Pascale, climate Physicist & IPCC Vice Chair for AR5
We welcome that the UK Parliament has just declared a Climate Emergency . It seems clearly apparent that this has been in no small part a response to the youth climate strikers and the growing wave of peaceful protests from civil society. What really matters now though, is what happens from here. Young people deserve on-going support so that policy responses and actions at all levels are made to align with the Paris Agreement.
Furthermore, as noted earlier, our climate is not the only planetary life-support system we are pushing to the brink. The newly published IPBES Global Assessment is clear that the scale of the decline of nature and accelerating extinction rates is “unprecedented and dangerous”. 
“Place the IPBES report next to the IPCC 1.5oC report and you have a full picture of a planetary emergency. Science cannot be more clear. The World needs to Transform. Now.”- J Rockstrom 
Young people are not asking adults to speak for them, but to listen to them, stand with them and act on behalf of planetary health and their future. As medical professionals signing this open letter, we pledge:1. On-going support for the youth “#FridaysForFuture” movement and school strikes as long as necessary to drive policy to what the science demands.2. To take action ourselves for climate and planetary health: individually and within our communities, institutions and clinical practice.
Signed: Dr. Jo-anne Veltman [author]Specialty Doctor Paediatrics, Norfolk and Norwich Hospital
References:1. https://www.ipcc.ch/sr15/2. https://news.un.org/en/story/2018/10/10224923. https://www.stockholmresilience.org/research/planetary-boundaries.html4. https://planb.earth/wp-content/uploads/2019/03/Hansen-letter-to-general-public.pdf5. https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(15)60854-6.pdf?code=lancet-site6. https://www.unicef-irc.org/publications/pdf/ccc_final_2014.pdf7. http://www.stateofglobalair.org/report8. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)32594-7/fulltext9. https://www.bbc.co.uk/news/uk-england-sussex-4737732710. https://twitter.com/JPvanYpersele/status/111683224593390387211. https://www.bbc.co.uk/news/uk-politics-4812667712. https://www.ipbes.net/news/Media-Release-Global-Assessment13. https://twitter.com/jrockstrom/status/1125469426692837377