Germany’s top climate scientist Jochem Marotzke admids: climate models were too sensitive
On October 5, 2018, German national weekly Spiegel presented a noteworthy interview with Germany’s top climate modeler, Jochem Marotzke, director of the Max Planck Institute for Meteorology in Hamburg.
Top German climate modeler, Jochem Marotzke, Director of the Hamburg-based Max Planck Institute for Meteorology. Image: Max Planck Institute for Meteorology.
Spiegel wrote in its sub headline:
Unexpected extra time in the climate scenario: ‘Our reprieve has been extended by about ten years’ Physicist and climate researcher Jochem Marotzke explains why humanity has more time to stop global warming than previously thought.”
Or in other words, German skeptics Dr. Sebastian Lüning and Prof. Fritz Vahrenholt write at their Die kalte Sonne blog, “the sensitivity of CO2 was obviously overestimated.”
Yes, the climate goalposts just got moved back once again.
Earlier skeptic claims of overly sensitive models now spot on
More than 6 years ago in 2012, Lüning and Vahrenholt had already pointed out the problem of over-sensitive models in their book “Die kalte Sonne” – a claim that Marotzke back then said was “completely outlandish”.
Naturally today Lüning and Vahrenholt find themselves somewhat vindicated, and are confident more vindication is on the way as the reality of climate change becomes increasingly known.
We can emit “at least twice as much”
In the Spiegel interview, conducted editor Olaf Stamp, Marotzke was asked about how much CO2 we could still add to the atmosphere:
MAROTZKE: […] According to the latest climate scenarios, the amount of CO2 that we may emit is far greater than previously assumed – a fundamental point.
SPIEGEL: So we’ve been given more time to reduce CO2 emissions?
MAROTZKE: Exactly. That’s what today’s improved models show. Our remaining CO2 budget for the 1.5°C target is in fact at least twice as much as previously thought: almost 1 trillion tonnes. Thus our reprieve has been extended about 10 years. Of course, it makes a huge difference if we have to bring the emissions of greenhouse gases down to zero in 15 years or 25 years. I assume that this will be the key message in the special report.”
And, according to Marotzke:
Our earlier models are too sensitive in one crucial place […]”