Source: BBC Radio 4: Today
URL: N/A
Date: 07/08/2018
Event: Rockström: we're "hitting the ceiling of the bio-physical limits of a stable planet"
Credit: BBC Radio 4, also many thanks to Ben Pile for transcribing this.
People:
Mishal Husain: And the current heatwave has probably made some people think about global warming in a new and more concrete way. A report released today is warning of the risks of a "hothouse Earth", triggered by global temperatures rising by around 2 degrees above pre-industrial levels. Currently we are at about a one-degree rise. The authors of the report warn that once we hit two degrees, the Earth's natural equilibrium could be irreversibly disrupted. We're joined by Professor Johan Rockström, executive director of the non-profit Stockholm Resilience Centre who is one of the authors of that report. Good morning, professor.
Johan Rockström: Yes, good morning.
Mishal Husain: Can you explain why you say that about a change in the Earth's natural processes?
Johan Rockström: Yes, we have so much scientific evidence today. To begin with from paleo-climatic science actually, showing that over the last one million years, the planet has quite harmoniously been shifting back-and-forth between ice age and inter-glacial periods of cycles of roughly one-hundred-thousand years. And we are now in an inter-glacial. We've been there since the last ice age – some twelve thousand years back. And at one degree Celsius rise of temperature that we have caused... humans have caused by burning fossil fuels predominantly... is the highest temperature on Earth since the last ice age. And we're reaching the edge of the highest temperatures on Earth in all the inter-glacials over the last one million years. So that shows that we're starting to reach, or hitting the ceiling of the bio-physical limits of a stable planet. Secondly, we have so much evidence today that the biosphere – the living, natural part of the planet – have the ability to absorb and dampen our warming by sucking up carbon dioxide, taking up heat, reflecting back heat from ice sheets. And that this capacity is what has kept the planet stable and that we risk crossing tipping-points, with these systems shift over from self-cooling to self-warming.
Mishal Husain: To - to -
Johan Rockström: Together this leads to the conclusion that this worry [?]
Mishal Husain: And you think that that kicks in at a rise of around two degrees Celsius?
Johan Rockström: We're starting to see the cracks in the resilience of the Earth's system. We have already one degree Celsius indications that rapid ice melts makes them... makes ice sheets absorb more heat than reflected back. We're seeing permafrost going. We're seeing... you know... lessened capability of oceans and land and forests to take up carbon dioxide. The scientists... science that is published start indicating that two degrees Celsius may be a threshold when these tipping points occur.
Mishal Husain: Yes, I mean, you you you say "may be", because what you're describing, isn't it a worst-case scenario... The point where rather than soaking up the carbon dioxide, the oceans and the former glaciers start chucking it out into the air?
Johan Rockström: No it's not a worst-case scenario. It's an intrinsic biophysical, non-negotiable part of how the Earth's system is configured. Somewhere out there, science shows clearly that there is a planetary threshold. The question is just where is it? When do systems like the oceans and forests tip over from being self-cooling to become self-warming? We now start seeing the scientific evidence that this threshold, this tipping-point may actually be at a lower temperature than we previously thought. And we're starting to see indications that it may be at two degrees.
Mishal Husain: Well, listening to that from Bonn is Ovais Sarmad who is the Deputy Executive Secretary from the United Nations Framework Convention on Climate Change – that's the organisation that work towards the Paris Accord. Good morning, Mr Sarmed.
Ovais Sarmad: Good morning to you and to the audience and professor.
Mishal Husain: What do you think of what you heard from Professor Rockström, this point about where the threshold is, to trigger this change in the, err, in the Earth's natural, err, processes? I mean, that, that, that, is something which has profound implications for policy.
Ovais Sarmad: Absolutely. Yes. And where we're sitting here from the United Nations, and actual physical location my office is just right one the river Rhine. And I'm seeing the river already receding and seeing the banks here on both sides of the river. It's quite scary and then Spain and Portugal struggling with forty degrees plus. Japan. Err, Greece seeing people fleeing to the sea. Sweden. California. Many other places and the... we're trying to bring all that science and the politics and the debate to closer to home, so to speak. And err, inform the world at large that, how serious it is. The situation... it's no longer cyclical and as the Professor said in very startling terms... scientific facts, that it is extremely serious and we have to do something about it now. And the Paris Agreement is the framework which has a very solid and robust framework [inaudible] to implement now, soon, sooner than... [inaudible under interruption].
Mishal Husain: Yes, but there are... there are a lot of doubts aren't there about whether it's going to be implemented as planned? And indeed even if sticking to err, to a two-degree target... even if it is possible to stick to that.
Ovais Sarmad: It is. There are of course the political challenges as it happens in multi-lateral systems but err, Paris Agreement is the only framework we have. And as international citizens, we need to stick to that and push as much as possible and that's exactly what we're doing. I'm actually an optimist and I'm very hopeful that, err, increasing the ambition and explaining to the general public the impacts and as we're seeing it now, we can prevent the damages that err, the professor explained.
Mishal Husain: Professor Rockström do you share that that that optimism, that the damage can be prevented or do you think we need a lot more ambition in policy on this area?
Johan Rockström: The damage can be limited. We also know that, err, we we not only can decarbonise the world economy in line with the Paris Agreement, we also benefit from it. We have more and more evidence about the economy, our health, socially, and equitably even security-wise, we gain from decarbonising and becoming sustainable. This paper lends scientific support for the Paris Agreement. And it shows that we should do everything we can to avoid reaching two degrees Celsius, as an aim for the one point five degrees. Remember that the writing is "stay well below two" in the Paris Agreement.
Mishal Husain: Johan Rockström, Professor Rockström and Ovais Sarmad of the United Nations, thank you both.