Gavin Schmidt has promised to answer your questions while riding a unicycle and juggling three machetes!
UPDATE: We are no longer taking new questions for Gavin. But check out the Q&A below—Gavin may have given an answer to something you wanted to ask.
Q: Geoff Way Gavin, do you incorporate ARGO data about the Ocean’s properties into your climate model? If you are ever in MA, I invite you to see where the najority of the ARGO floats are made.
A: Gavin The Argo floats, for those that don’t know, are a network of over 3000 sensors that drift in the ocean and report back via satellite how warm or cold the ocean is. They provide data that can be used together with more historical measurements to see how the ocean temperatures are changing. Our climate models don’t use the data directly, but the changes in temperature that the models produce do get compared to this network over short and long time scales. And yes, I’d love to come by and see them made!
Q: Jackenson Durand Dear Gavin, - Are we responsible of our own Ozone degradation problematic? Or, - Do our current Earth aspects catastrophic natural are in liaison of his history orbital change, occurring at a specific astrologic calendar?
A: Gavin Stratospheric ozone depletion is a separate environmental problem than climate change - though there are connections. The main ozone depleting chemicals (CFCs) are also greenhouse gases, and the chemical reactions that these chemicals catalyse are also affected by temperatures (which are also changing).
Wobbles in the Earth’s orbit (because of the tug of the other planets mainly) do cause climate change - but these changes are very slow (10s of the thousands of years to happen) and are not related to what we are seeing at the moment.
Q: Gina Do you have a standard (short) response to the people that state that global warming is not scientifically proven? And, how do you respond to those that bring up the climate change e-mail fiasco? Thanks-love the interviews NOVA!
A: Gavin Well, there’s no doubt that the planet is warming up - you get that from weather stations, ocean observations, reducing sea ice, retreating mountain glaciers, the earlier onset of spring etc. However, your question is probably more related to whether humans have had a role in this. That is a harder thing to demonstrate - but just like in a trial, you have to look at the balance of evidence.
The main suspects - human caused increases in greenhouse gases like CO2 and CH4 - have their fingerprints all over the climate, while other factors - like the sun, or volcanoes, or the oceans - all seem to have alibis. We can explain most of what has happened over the last century (and for many times in the deeper past too) using our current knowledge about climate (including the role of greenhouse gases), and when we project that forward using the accelerating rise in CO2, it looks like the planet will warm a lot more.
So the issue is not really whether we can prove absolutely that humans are causing this (since absolute proof doesn’t exist outside of pure mathematics in any case), but rather how we deal with what the science strongly suggests might happen in the future.
As for the emails, I think these NOVA videos are a much better insight into my secret life!
Q: Betsy Hi Gavin, What was the one thing that you had to do over and over again until you were satisfied with the result? What made it harder to succeed in that goal?
A: Gavin Juggling is full of efforts like this. Some of which I succeeded at (5 balls), some of which I’m still pursuing (4 balls mill’s mess). But these things are appreciated by others precisely because they are hard. So it is the goal itself that makes it hard to succeed. What would be the challenge otherwise?
Q: Denis AP Environmental Science teacher
Just want to thank you for your efforts at RealClimate.org. I’ve used it to improve my own understanding of climate change in preparation for working with my students.
A: Gavin Thanks! It’s nice to know it’s worthwhile.
Q: Ann H. Batum Hello Gavin, Do you include orbital variations and axial tilt as part of climate predictions? If they are important, why don’t I hear about them? Thanks. Ann
A: Gavin Good question! The answer is yes. However, these changes in the orbit are quite slow (thankfully!). To give you an example, the date at which the planet is closest to the sun is around Jan 3 right now (during the northern hemisphere winter). Around 6000 years ago, it was in August. That led to northern hemisphere summers then being warmer than they are now with all sorts of implications for rainfall patterns, glaciers and the Arctic. Other parts of the world reacted but in different ways - for instance the tropical areas cooled a little. So when we are trying to simulate climate changes during that period, the orbital shift is important. However, for climate changes in more recent periods (say the last few decades or the next century), these orbital changes are too small to have much of an effect.
Q: Lyle How many miles are there between each degree of latitude?
A: Gavin That’s easy enough to work out - the great circle circumference around any latitude is 2piR where R is the radius of the Earth and one degree of latitude is 1/360th of that. Given that R is around 3,950 miles, you get around 70 miles for one degree of latitude.