NASA scientists take to Reddit to issue a dire warning

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NASA scientists take to Reddit to issue a dire warning

• Jeremy Berke
 
• Jan. 21, 2016, 8:37 PM 
• 419

Climate change and sea level rise have radically affected Kiribati.REUTERS/David Gray

By now, you've probably heard that 2015 was declared the hottest year on record.

On Thursday afternoon, two climate experts from NASA, Gavin Schmidt and Reto Ruedy, fielded questions in a Reddit Ask-Me-Anything thread on climate science.

While this weekend's predicted monster snowstormwill no doubt have those of us who live in the Northeast wishing for some heat, you should consider it a good sign that the snow is still falling.

Here are some of the best questions and answers from the thread (some have been lightly edited and condensed):

What can I do, as an individual or family, that can have the biggest impact on helping to prevent some of the negative effects of climate change?

Electing and working for a government that takes science seriously is probably your most potent weapon. (Ruedy)

What would you say to the current presidential candidates about their stances on climate change? How would you attempt to change their minds? What is our best option to get society more invested in climate change and science in general?

Speaking personally, I'd like all policy-makers to take this seriously and craft their policies on the environment and energy with as much input from the science community as possible. The resources available to help decision makers estimate the climate and air quality impacts of their choices are vast, and should be better utilized than they have been. (Schmidt)

Is there a irreversible point in the climate change, and if so, then where do we stand now?

What we are doing is fiddling with a thermostat - the amount of greenhouse gases in our atmosphere - turning it up. There is an irreversible point, but we are not anywhere close to it in my opinion. (Ruedy)

People protest against climate change during a demonstration in Quebec City April 11, 2015.Mathieu Belanger/Reuters

What do you say to the folks who don't believe your work? The folks that don't believe in global warming?

All I can do in this case is remind them that nature is not kind to the unaware. The laws of physics will do their thing whether we accept them or not. I personally don't understand the law of gravity, nobody could explain to me why a stone falls to the ground without being pushed or pulled by something visible. However, I will not step off the roof of a high building expecting that my not understanding will protect me. (Ruedy)

'Belief' is not the right word. Scientists talk about anthropogenic global warming because that's the best explanation we have for a whole host of different observations we have that is rooted in basic (and well-understood) physics. (Schmidt)

A dried lake bed in Bolivia.Reuters/David Mercado

I heard that Earth has been through warming and cooling phases for a very long time. First, how do we measure what the Earth's temperature was before modern technology? Second, how do we decide what is natural global warming and what is human-affected warming?

There are lots of pieces of evidence of past climate changes - ice cores are important, cave records, ocean sediment etc. - and, yes, they do reveal a dynamic range of climate variability in the past - particularly before the Holocene (the current interglacial period). Understanding what causes those changes is a big part of climate science and an important test of the climate simulations that my group (and others) do.

The second part of your question refers to 'attribution' and for that we try and calculate the fingerprints of change that would be associated with any particular cause or some specific internal oscillation. For the 20th century and more recently, we have looked at multiple possible causes - volcanoes, the sun, deforestation, air pollution and greenhouse gases and find that the human fingerprint is increasingly dominant. (Schmidt)

What we experience now is a change that is much faster than anything humanity experienced so far and it can only be explained by taking the greenhouse effect and the increase in greenhouse concentration into account. The models are extremely useful and trustworthy to answer that question. (Ruedy)

How much did the warming El Niño trend contribute to this finding?

The 2015/2016 El Niño will most affect 2016, not 2015. However, we've been in El Niño conditions since the summer, and we saw an spike in October, November, and December that was related to that. You can normalize the index using regression analysis, and get an El Niño-corrected version. 2015 would still be a record. (Schmidt)