Daily Archives: August 21, 2018

Should we block out the sun to stop climate change? | NASA’s Michelle Thaller

Big Think

Published on Jul 5, 2018

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Lisa, I share your concern about climate change. This is something that’s one of the biggest challenges that humanity has ever faced, and it’s something that in the next couple of decades and centuries we’re going to have to really band together and work together to solve.

And when you ask a question like you did, about “how might you solve climate change,” it actually gives me a lot of hope because it means that young people like you are really starting to think about ideas about how we could address climate change.

You said, “could you build a giant disk and put it between the earth and the sun and have it act as a kind of sunshade actually cooling down the earth?” That’s a wonderful idea. There are some things about that that would be quite difficult and one thing is that the sun is actually very large, it’s much larger than the earth, so it actually projects light around anything that you put up there.

You’d have to put a very, very large disk up there. It might have to be something roughly the size of the planet in order to shade the planet effectively against the sun. So that’s something that might be possible, but it would be very expensive and difficult to construct. But I love the fact that you’re thinking about it.

It does however to me sort of not address the underlying problems with climate change. A lot of people have ideas similar to yours that, what if we could just block out some of the sun’s light, would that actually make climate change go away? And one of the ideas people have is possibly launching lots and lots of particles of dust up into the atmosphere.

We observed that when there’s a volcanic explosion and the earth naturally puts lots and lots of dust up into the atmosphere, the earth’s climate cools. We observed this in the ‘90s when Mount Pinatubo erupted and we actually had a decline, a little bit of a notch on the global warming, just due to this volcano putting lots and lots of stuff up into the atmosphere.

So could we do that artificially could we just darken our atmosphere to actually have less sunlight get through? The answer is yes, we probably could, but it would be a huge effort.

A single volcano puts up many, many thousands of tons of dust up there, so this would have to be something continuous: lots and lots of rockets or aircraft distributing dust across the atmosphere. And the thing that kind of frightens me is that we really don’t understand our atmosphere enough to know what that sort of cooling would do. The atmosphere stores heat, it creates winds and of course the air moves around, there are storms; scientists spend a lot of time studying how the atmosphere stores heat, how the weather forms, and when you darken the atmosphere I’m not sure what it would do to our weather. It would be a very dangerous experiment to do if you couldn’t control it.

And the same thing with building a disk: I’m not sure that darkening the earth is a very good idea; it may change things like weather patterns or even ocean currents, the winds, all of that. It also doesn’t get at the problem of carbon dioxide.

Now the reason our atmosphere is getting warmer and warmer and warmer is because we humans are putting lots of carbon dioxide up into the atmosphere and this acts as what we call a greenhouse gas. Sunlight can get through the atmosphere but the carbon dioxide traps it and it can’t release itself back into space so it gets warmer and warmer over time. Carbon dioxide doesn’t just warm the atmosphere, it also affects our oceans. When ocean water combines with carbon dioxide it creates something called carbonic acid and it makes the oceans more and more acidic over time and this is a really big problem for marine life. There are things like algae, the algae in the oceans are responsible for most of the oxygen that we breathe, and the algae are having trouble forming because of the higher acid levels in the ocean.

#RiseForClimate Live Coverage Tips


Published on Aug 21, 2018

If you’re planning an action or event, and want to know how to best cover it online using just your mobile phone (and a few other tools) — here are 5 tips.

Univ of New Hampshire becomes first state school to accept Gaokao scores

CGTN America
Published on Aug 21, 2018

There are more than a million international students in the United States and Chinese students make up about a third of them. Now, one American university is making the enrollment process a bit easier. And it isthe first of its kind in the country to do so. CGTN’s Frances Kuo reports.

Environmental Protection Agency Replaces Obama-Era Rules To Benefit Coal | Here & Now

August 21, 2018 The Environmental Protection Agency announced its plan to roll back an Obama-era plan to limit greenhouse gas emissions. The new rules instead loosen restrictions on coal-fired plants and allow states more autonomy to set their own climate policies.

Here & Now‘s Jeremy Hobson takes a closer look with NPR energy and environment editor Jennifer Ludden (@JenniferLudden).

This segment aired on August 21, 2018.

Climate Code Red: Beware the “fat tail”: Climate risk and scientific reticence

by David Spratt

How should we respond to climate change, avoid catastrophe and get back to safer conditions? The question is often posed in “risk-management” terms, but what does than mean in assessing the risks associated with climate change, the possible impacts and the speed of action required?

We have historically tended to underestimate the rate of climate change impacts.

Too often policy is based on consensus scientific projections that downplay what Prof. Ross Garnaut called the “bad possibilities”, that is, the relatively low-probability outcomes that have very high impacts. These events may be more likely than is often assumed, as Prof. Michael E. Mann explained in reviewing Climate Shock: The Economic Consequences of a Hotter Planet:

One of the most under-appreciated aspects of the climate change problem is the so-called “fat tail” of risk. In short, the likelihood of very large impacts is greater than we would expect under typical statistical assumptions… There is… a greater likelihood of warming that is well in excess of the average amount of warming predicted by climate models… This is further compounded by the fact that the damages caused by climate change — i.e. the consequence — also increases dramatically with warming. That further increases the associated risk. With additional warming comes the increased likelihood that we exceed certain “tipping points”, such as the melting of large parts of the Greenland and Antarctic ice sheet and the associated massive rise in sea level that would produce.


Figure 1: Climate change “fat tail” risks

This “fat tail” risk is illustrated in Figure 1, where a greenhouse concentration may have a most likely outcome of ~3°C of warming, but a greater than 10% risk of warming of greater than 6°C.

In his 2011 climate science update for the Australian Government, Garnaut questioned whether climate research had a conservative “systematic bias”.

He wondered if most of the new knowledge either “confirms the established (climate) science or changes it for the worse”, but rarely finds a need to lower the magnitude of the threat, is due to “scholarly reticence”. Garnaut pointed to a pattern across diverse intellectual fields of research predictions being “not too far away from the mainstream” expectations and observed that in the climate field that this “has been associated with understatement of the risks”.

…(read more).

When the science is so clear, why is the argument so clouded?

While the evidence for climate change continues to strengthen, public acceptance of the science keeps declining. Closing the gap could be a question of better communication.

At the commencement of the Garnaut Climate Change Review, I faced the question that confronts all who are not climate scientists and who are required for one reason or another to take a position on the climate science: how do we know if propositions put forward by some climate scientists are right?

By the time I concluded the Review in September 2008, I had read a fair bit of climate science, published by people, including some “sceptics”, with genuine credentials and records of publication in professionally reputed scientific journals. I was exposed to more of the literature through the work of a conscientious team in the Review’s secretariat, and of scientists advising me in various ways.

Few who contributed to the real climate science doubted that the average temperatures on earth were rising, and that this reflected the increase in concentrations of greenhouse gases in the atmosphere as a result of human activity.

This view was supported by the learned academies in all of the countries of scientific achievement and the overwhelming majority of specialists in the core disciplines contributing to climate science.

As I noted in the Review, there is no genuinely scientific dissent from the main propositions of the physics of climate change that increased concentrations of greenhouse gases raise the earth’s temperature by calculable amounts. The premise on which I worked through the 2008 Review was that the main propositions of the mainstream science were right “on a balance of probabilities”.

…(read more).

We’ve reached a Point where we have a Crisis, an Emergency

Climate State
Published on Aug 20, 2018

David Spratt (Breakthrough Institute), speaks 2014 at the Royal Melbourne Institute of Technology about climate change, myths, and realities. His latest 2018 report “What Lies Beneath” with a foreword by Hans Joachim Schellnhuber can be read here https://www.breakthroughonline.org.au… For more visit http://www.climatecodered.org/2018/08… “We’ve reached a point where we have a crisis, an emergency, but people don’t know that. …There’s a big gap between what’s understood about global warming by the scientific community and what is known by the public and policymakers”. – James Hansen, 2008
Source Environment Victoria