Global warming operates according to a simple law of physics: carbon-based compounds trap thermal energy (heat) the way glass in a greenhouse does. It is because we have enough carbon-based compounds in our atmosphere that the Earth has a climate conducive to human existence. Were that greenhouse effect not at work, most life on Earth would have a hard time surviving. But too much heat also destabilizes the complex natural systems that have adapted to sustain life as we know it.
With more carbon dioxide accumulated in our atmosphere and oceans than at any moment in the entire history of the human species, we are observing a steady increase in global average temperatures. Those increased temperatures represent excess thermal energy, and that excess thermal energy is destabilizing climate patterns we have come to rely upon. We have built a global civilization that relies on relatively stable climate conditions, which have persisted since before our species existed, and which have made it possible to reliably access life-sustaining resources.
In the educational TV series Cosmos, astrophysicist Neil deGrasse Tyson explains that weather varies widely, even over the short term, while climate traces a long-term trend. He walks along a beach with a dog on a leash, and the dog does what dogs do, flitting from one side to the other, following scent trails that go entirely unnoticed by his human companion. The dog is like the weather, zig-zagging, disorderly, operating moment to moment; the climate is the human being walking the dog, following a mostly straight line, keeping weather extremes on a leash. With a longer view and steadier gait, the climate is more self-regulating, more given to order and stability.
DeGrasse Tyson’s brilliant explanation points to a number of subtle but important truths: weather, which is unpredictable on the whole, is kept more regular by a stable climate. The leash can be lengthened or shortened, so the extremes in weather’s zig-zag pattern can be made more or less severe. A warmer climate gives a longer leash, letting weather go to more intense extremes.
The atmosphere, oceans, and land, are all warming at rates far faster than the geological record shows to be the norm. Atmospheric temperatures have been increasing steadily, in line with increasing concentrations of greenhouse gases. The oceans are absorbing excess thermal energy at 20 times the rate of the atmosphere. And we are observing not only pervasive glacial melt, but also an escalating deep thaw in Arctic permafrost.
With air, water, and land all warming, climate patterns are being destabilized. The intensity of extreme events is increasing, and once-stable climate patterns keeping weather from getting too unpredictable are increasingly destabilized and dislocated. It might be an oversimplification to say that California’s missing water is hiding out in Boston’s record snowfall, but that meme does help to highlight the problem inherent in climate pattern dislocation.
Entire climate patterns are dislocating, leaving some regions without much-needed precipitation, while pushing far more precipitation into regions where various climate patterns converge. So, we see persistent exceptional drought in California and persistent exceptional precipitation in New England. This is also why the Polar Vortex (not a storm, but actually a circular wind current that normally stays in the Arctic and helps to keep the Arctic and sub-Arctic climates defined and separate) has been migrating south during the winter.
Much of North America has, this year, been living inside an Arctic climate system that has dislocated to latitudes where it does not normally reside. So, it is the first day of spring in New Jersey, and we have still more snow. And if you have been in touch with anyone from the northeast this winter, you have probably been hearing the amazed expression “More snow?!” with accelerating frequency. This is the dislocation of climate patterns touching your life, whether you are living it, or just hearing about it from someone who is.
In fact, across the world, this has been the warmest northern winter ever recorded; some places have experienced unprecedented warmth, while others have seen unprecedented cold. It has routinely been colder in New York and New England this year than it has been in Juneau, Alaska. We are also seeing unusual events where the day after what would appear to be a routine rainfall, major flooding will occur downstream, as snowmelt runoff floods a watershed (as happened with the Delaware River last year) with an uncommon amount of excess water.
Meanwhile, across central Africa and south Asia, there is increasing concern that monsoon rains will persistently fall off land, or in other regions, leaving hundreds of millions of people living with exceptional drought and far too little food and water. While the occurrence of one particular weather event can’t be entirely attributed to climate change, such an overwhelming and persistent trend can be described as the dislocation of climate systems: climate destabilization.
Climate destabilization has come to us sooner than many expected. One of the reasons we hear the general term “climate change” so often is because scientists don’t like to make predictions very far into the future. It was expected that our impact on Earth’s dominant climate patterns would continue to evolve, gradually, and that change would be compounded as major shock events and positive (trend-reinforcing) feedback loops drive an acceleration of the underlying physical problem at work in our atmosphere and oceans. It was thought destabilization would lie in wait some decades into the future; scientists are natural skeptics and weren’t inclined to see deep shocks to the climate system happening so soon.
But in just 15 years, we have moved from having one major drought a year to having them on all continents simultaneously, on a more or less ongoing basis. With multiple major agricultural regions experiencing severe water stress and/or ongoing drought conditions, simultaneously, the question of whether warming is happening is virtually a red herring: the real problem is the destabilizing effect climate stress is having on economies and on political systems, around the world.
When you read reports about the deepening chaos in Yemen, keep in mind that Yemen is the first country in the world to effectively “run out of” fresh water. Entire towns and cities rely on water being trucked in, and political instability is making it near impossible to grow food or provide water for their populations. Some towns have formed local militia whose purpose is to ensure rivals (those on the other side of the water) don’t leave their people literally without a lifeline. When there is no water, society can quickly degenerate into a situation where there are rivals on all sides.
In the North Atlantic, during the hottest year on record, an anomalous cold patch emerged off the coast of Greenland. This was the result of huge volumes of fresh water, from land-based ice melt, pouring into the Atlantic Ocean. The excess low/temperature fresh water has the effect of slowing down the Gulf Stream, which brings warmer temperatures to northwestern Europe. This then interferes with the Atlantic Meridional Overturning Circulation, which pushes heavier cold water down to the ocean floor and into the global “conveyor belt”, which has a regulating influence on climate.
Some places are experiencing extreme drought or heat, others are seeing unprecedented precipitation, flooding or even isolated cooling. These observations are all related to the behavior of a destabilized climate system, less able to regulate volatile weather patterns. The overall process stems from an excess of thermal energy moving through Earth’s atmosphere and oceans. Was the late-March snowfall in your back yard put there by warmer local temperatures? No. Is it part of an escalating slippage occurring in climate patterns across the world? Yes.