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Short Answers to Hard Questions About Climate Change

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Justin Gillis reports in the NY Times:

The issue can be overwhelming. The science is complicated. Predictions about the fate of the planet carry endless caveats and asterisks.

We get it.

So we’ve put together a list of quick answers to often-asked questions about climate change. This should give you a running start on understanding the problem.

1. How much is the planet warming up?

2 degrees is actually a significant amount.

As of early 2017, the Earth had warmed by roughly 2 degrees Fahrenheit, or more than 1 degree Celsius, since 1880, when records began at a global scale. That figure includes the surface of the ocean. The warming is greater over land, and greater still in the Arctic and parts of Antarctica.

The number may sound low. We experience much larger temperature swings in our day-to-day lives from weather systems and from the changing of seasons. But when you average across the entire planet and over months or years, the temperature differences get far smaller – the variation at the surface of the Earth from one year to the next is measured in fractions of a degree. So a rise of 2 degrees Fahrenheit since the 19th century is actually high.

The substantial warming that has already occurred explains why much of the world’s land ice is starting to melt and the oceans are rising at an accelerating pace. The heat accumulating in the Earth because of human emissions is roughly equal to the heat that would be released by 400,000 Hiroshima atomic bombs exploding across the planet every day.

Scientists believe most and probably all of the warming since 1950 was caused by the human release of greenhouse gases. If emissions continue unchecked, they say the global warming could ultimately exceed 8 degrees Fahrenheit, which would transform the planet and undermine its capacity to support a large human population.

2. How much trouble are we in?

For future generations, big trouble.

The risks are much greater over the long run than over the next few decades, but the emissions that create those risks are happening now. This means the current generation of people is dooming future generations to a more difficult future.

How difficult?

Over the coming 25 or 30 years, scientists say, the climate is likely to resemble that of today, although gradually getting warmer, with more of the extreme heat waves that can kill vulnerable people. Rainfall will be heavier in many parts of the world, but the periods between rains will most likely grow hotter and drier. The number of hurricanes and typhoons may actually fall, but the ones that do occur will draw energy from a hotter ocean surface, and therefore may be more intense. Coastal flooding will grow more frequent and damaging, as is already happening.

Longer term, if emissions continue to rise unchecked, the risks are profound. Scientists fear climate effects so severe that they might destabilize governments, produce waves of refugees, precipitate the sixth mass extinction of plants and animals in the Earth’s history, and melt the polar ice caps, causing the seas to rise high enough to flood most of the world’s coastal cities.

All of this could take hundreds or even thousands of years to play out, but experts cannot rule out abrupt changes, such as a collapse of agriculture, that would throw civilization into chaos much sooner. Bolder efforts to limit emissions would reduce these risks, or at least slow the effects, but it is already too late to eliminate the risks entirely.

3. Is there anything I can do about climate change?

Fly less, drive less, waste less.

You can reduce your own carbon footprint in lots of simple ways, and most of them will save you money. You can plug leaks in your home insulation to save power, install a smart thermostat, switch to more efficient light bulbs, turn off the lights in any room where you are not using them, drive fewer miles by consolidating trips or taking public transit, waste less food and eat less meat.

Perhaps the biggest single thing individuals can do on their own is to take fewer airplane trips; just one or two fewer plane rides per year can save as much in emissions as all the other actions combined. If you want to be at the cutting edge, you can look at buying an electric or hybrid car, putting solar panels on your roof, or both.

If you want to offset your emissions, you can buy certificates, with the money going to projects that protect forests, capture greenhouse gases and so forth. Some airlines sell these to offset emissions from their flights. You can also buy offset certificates in a private marketplace, from companies such as TerraPass; some people even give these as holiday gifts. In states that allow you to choose your own electricity supplier, you can often elect to buy green electricity; you pay slightly more, and the money goes into a fund that helps finance projects like wind farms.

Leading companies are also starting to demand clean energy for their operations. You can pay attention to company policies, patronize the leaders, and let the others know you expect them to do better.

In the end, though, experts do not believe the needed transformation in the energy system can happen without strong state and national policies. So speaking up and exercising your rights as a citizen matters as much as anything else you can do.

4. What’s the optimistic case?

Several things have to break our way.

In the best case that scientists can imagine, several things happen: Earth turns out to be less sensitive to greenhouse gases than currently believed; plants and animals manage to adapt to the changes that have already become inevitable; human society develops much greater political will to bring emissions under control; and major technological breakthroughs occur that help society to limit emissions and to adjust to climate change.

Some technological breakthroughs are already making cleaner energy more attractive. In the United States, for instance, coal has been losing out to natural gas as a power source, as new drilling technology has made gas more abundant and cheaper; for a given amount of power, gas cuts emissions in half. In addition, the cost of wind and solar power has declined so much that they are now the cheapest power source in a few places, even without subsidies.

Unfortunately, scientists and energy experts say the odds of all these things breaking our way are not very high. The Earth could just as easily turn out to be more sensitive to greenhouse gases as less. Global warming seems to be causing chaos in parts of the natural world already, and that seems likely to get worse, not better. So in the view of the experts, simply banking on rosy assumptions without any real plan would be dangerous. They believe the only way to limit the risks is to limit emissions.

5. Will reducing meat in my diet really help the climate?

Yes, beef especially.

Agriculture of all types produces greenhouse gases that warm the planet, but meat production is especially harmful — and beef is the most environmentally damaging form of meat. . .

Continue reading.

There’s a lot more information. Later in the article:

Perhaps the greatest fear is a collapse of food production, accompanied by escalating prices and mass starvation. It is unclear how likely this would be, since farmers are able to adjust their crops and farming techniques, to a degree, to adapt to climatic changes. But we have already seen heat waves contribute to broad crop failures. A decade ago, a big run-up in grain prices precipitated food riots around the world and led to the collapse of at least one government, in Haiti.

Another possibility would be a disintegration of the polar ice sheets, leading to fast-rising seas that would force people to abandon many of the world’s great cities and would lead to the loss of trillions of dollars worth of property and other assets. In places like Florida and Virginia, towns are already starting to have trouble with coastal flooding.

Scientists also worry about other wild-card events. Will the Asian monsoons become less reliable, for instance? Billions of people depend on the monsoons to provide water for crops, so any disruptions could be catastrophic. Another possibility is a large-scale breakdown of the circulation patterns in the ocean, which could potentially lead to sudden, radical climate shifts across entire continents. . .

The risk is that the rate [of sea level rise] will accelerate markedly. If emissions continue unchecked, then the temperature at the Earth’s surface could soon resemble a past epoch called the Pliocene, when a great deal of ice melted and the ocean rose by something like 80 feet compared to today. A recent study found that burning all the fossil fuels in the ground would fully melt the polar ice sheets, raising the sea level by more than 160 feet over an unknown period. Many coastal experts believe that even if emissions stopped tomorrow, 15 or 20 feet of sea-level rise is already inevitable.

The crucial issue is probably not how much the oceans are going to rise, but how fast. And on that point, scientists are pretty much flying blind. . .

Written by LeisureGuy

10 July 2017 at 12:23 pm

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