A couple of weeks ago, in the wonderful HBO series The Newsroom, a climate expert told the news anchor that it’s now too late to save Earth. Catastrophe cannot be avoided. We needed to take action ten or 20 years ago. We have already hit a carbon dioxide level of 400 parts per million (ppm), and nothing can stop it from reaching 500 ppm by around 2065.
Long-suffering readers will recall that in the ’90s, before Al Gore and his film An Inconvenient Truth, this page ranted and raved about carbon dioxide. I was pretty obsessed with it. Then came 1998 – by far the warmest year in modern history – and it really seemed as if the Apocalypse was beginning. Now, yesterday, a good friend who saw that Newsroom episode wrote an anxious letter saying that he was going to urge his college kids not to have children, because the world is screwed and there’s no hope.
Is it true? Are we toast? Or, instead, is there an optimistic outlook that can be compatible with the facts at hand? That’s where I’m going today: to show a possible brighter side of global warming, without requiring that one become a card-carrying climate-denier.
In any event, we should do our part to limit carbon. Personally, I have a hybrid car and have just gotten bids on having my roof plastered with solar panels, which are becoming popular. Meanwhile, the US is replacing much of its coal usage with natural gas, which emits one-fourth the carbon for the same energy. The handwriting is on the wall: Reduced carbon will be a reality as the century progresses. But it is it really too late?
It’s actually pretty easy to say no. The fact is, the global temperature increase has been very minor so far. This very small rise is something that no one can explain. Perhaps it has to do with the Sun’s present extended low level of activity; a full chapter in The Sun’s Heartbeat makes that case. Global temperatures have climbed only 1.5 degrees since 1900, despite the huge amount of carbon that we’ve put into the atmosphere.
CO2 has gone from its natural background rate of 292 ppm to the current 400 ppm, and will ultimately probably hit 500 ppm. Therefore, about 50 percent of this possible projected rise from 292 to 500 ppm has already taken place, without causing any major unfavorable climate change – unless you count Arctic summer sea ice melting. And since the radiative effects of CO2 are almost certainly logarithmic, more than 65 percent of any climatic influences have already occurred. So where are they?
It remains possible that it will not significantly happen at all. Remember, a slightly warmer climate may well be good for Earthly life. It’s certainly good for forests and plants to have more CO2. They love it: The botanical world is already responding favorably to the enhanced carbon dioxide. If it weren’t for the population boom to the current 7.2 billion, I would say that we shouldn’t worry at all. Too many people wanting the American living standard are the real problem.
A few degrees warmer at night – which is where greenhouse gas-based increases must happen – will also increase rainfall, which is more good than bad. Certainly, vast stretches of taiga, plus huge tracts like southern Canada where the growing season has traditionally been too short for major crops, are already becoming usable farmlands for the first time.
Sea-level rises are proving hard to pin down. The ocean rose seven inches in the 20th century. Some estimate that it will rise three feet in the 21st. That would be expensive in terms of periodic flooding in places like Western Europe and parts of the US, and force massive relocations in low-lying regions like Bangladesh. However, the sea level rate shrank during the past decade, so nobody knows what’s going on for sure. Half of any increase is due to the simple fact that warmer water expands. Most of the rest of the rise is due to melted ice. Now, Greenland ice is indeed melting and contributing, but Antarctic ice, a much bigger repository, may actually be going in the opposite direction because of enhanced snowfall that is thickening that continent – although, more ominously, the Amundsen glaciers do show significant melting in the western part of that continent.
Meanwhile, no one is sure about how much carbon the ocean can suck up. It was thought that only the upper few hundred meters matter, because it takes water layers too long to mix down. Newer estimates say that deeper sea layers mix up much more rapidly, and thus will continue to do the job of absorbing atmospheric carbon indefinitely. Similarly, estimates of the lifetime of enhanced CO2 in the air are often cited as centuries. But some scientists think that once we reduce carbon, it will only take decades for the sea, plants and earthly rocks to absorb what’s there.
So hang in there: This chapter has not been written. It is far from certain that anything truly catastrophic will unfold. Maybe the effects will be negative, but minor. Maybe we’ll see more frequent violent weather events; maybe a quasi-permanent increase in drought out west and more rainfall here in the east. It may be nothing that we cannot adapt to.
It may be too late to stop the carbon, but it’s way too early to despair. Let’s just do our part – and see what happens.
Want to know more? To read Bob’s previous “Night Sky” columns, visit our Almanac Weekly website at HudsonValleyAlmanacWeekly.com.