GETTING ACCLIMATED: CLIMATE CHANGE GLOSSARY 101

Courtesy of Richard Alley   As the earth loses dramatic ice monuments to global warming, the meltwater is raising sea levels and threatens coastal areas with flooding.
Courtesy of Richard Alley
As the earth loses dramatic ice monuments to global warming, the meltwater is raising sea levels and threatens coastal areas with flooding.

It’s easier to understand climate change– and even to do something about it– if you know a little of the lingo. Top scientists from around the globe agree that the world is heating up at an increasing rate, and understanding the process is essential to halting it. Familiarity with climate terms and phrases can become a bridge for understanding the issue on a broader scale. A basic climate change vocabulary is essential to connecting the dots between climate and your life in a changing environment.  

The Big Dry/The Big WetClimate scientists often focus their studies on specific areas of the world, and then come together to share findings with one another in order to get a full view of today’s warming effects. The Big Dry and the Big Wet refers to climate changes that are taking place in Australia, where floods ravage Queensland while, at the same time, Tasmania is plagued by extreme drought and heat. Experts need to better understand the Big Dry and the Big Wet but, in general, they know that climate change means rising sea levels with coastal flooding and more inland drought.

Bipolar SeesawThe world’s ocean waters move in and out of one another as warm water flows north and pushes cooler water south, a process known as thermohaline circulation. But this conveyor system operates in a delicate balance. As the globe heats up and glaciers begin to melt, thermohaline circulation can accelerate, throwing this balance out of whack. This effect is known as the bipolar seesaw, where climate shifts accelerate in the north and are out of phase with temperatures in the south due to the vast redistribution of heat via the conveyor.

Cosmic Ray Dating
Believe it or not, scientists can use cosmic rays to date icebergs and accurately identify the history of climate change on earth. Cosmic rays are subatomic particles accelerated in the shock waves of exploding stars and hurled across the galaxy, including through our solar system. Cosmic rays piercing into the atmosphere create Beryllium-10 and other isotopes that fall to the earth’s surface and continue to decay. Evidence of these atoms imbedded in ice can help identify when certain warming events have taken place through the years.

Ice CoresUsing special drills, scientists are able to cut into glaciers and drill down, pulling out three-foot-long, four- to five-inch-wide cylinders, or ice cores. Ancient air pockets that include carbon dioxide gas, a thermostat for climate change, can be used to identify climate records going back hundreds of thousands of years.

Ice RaftingDebris can be carried hundreds or even thousands of miles by ice, whether it’s via a glacier advancing or simply via a chunk of ice that’s broken off into the ocean. The long trek is called ice rafting. Dirt and rock was carried via ice rafting and later dumped into the ocean during the last ice age. Scientists drilling into ocean sediments can identify six massive meltings associated that layers of sediments and related to worldwide climate change.

Courtesy of Jorge Strelin   Current view of the Southern Patagonian ice fields
Courtesy of Jorge Strelin
Current view of the Southern Patagonian ice fields

Ice SheetsWhen it comes to ice, is anything bigger than a glacier? If it measures larger than 20,000 square miles, then yes, and it’s called an ice sheet. One-tenth of the earth’s surface is buried by ice. The Antarctic and Greenland ice sheets (the only current ice sheets on earth) are the major contributors.

Little Ice Age/Last Ice AgeThe Little Ice Age refers to a cold period that lasted from the fourteenth to the mid-nineteenth century. But the last full-scale ice age ended about 11,500 years ago. In order to get a more accurate picture of the earth’s warming, climate scientists have labeled climate periods dating back hundreds of thousands of years by studying ice cores drilled from the glaciers.

MeltwaterAs the globe warms, glaciers slowly begin to melt and shrink back. Scientists can measure a glacier’s meltwater over the course of a year to track the results of climate change on the world’s glaciers. Years of more meltwater versus years of less meltwater can mean different scenarios for the big picture of climate change.

MoraineAs glaciers advance and retreat, they leave rock and dirt behind on land ans well as in the seas. Over time, this debris can accumulate and form a moraine, or a long, ridged hill. Scientists can point to moraines to help identify the effects of climate change and to date the retreat of the glaciers in the past ice age.

Ocean Conveyor Belt
Warm waters and the salt content of the oceans determine the water’s overall density. As surface waters are driven north by winds, the oceans ultimately mix together in deep-sea basins, with heavier water sinking and driving cooler water to the south. Also known as thermohaline circulation, this refers to the overall circulation of the oceans across the globe.

Sea IceBecause ocean waters contain salt, freezing and climate change occurs differently than it would in fresh water. Sea ice refers to frozen ocean water, as opposed to icebergs, which are frozen fresh water.

Westerlies Winds play a large role in climate change, as they direct cyclones, move the surface ocean waters and ultimately aid in the flow of the ocean conveyer belt. The Westerlies are the winds between 35 and 65 degrees latitude that blow from west to east. They primarily come from the northwest in the southern hemisphere and the southwest in the northern hemisphere.

Courtesy of Adi Torfstein   Morianes, ridges of debris left by past glaciers, near the Dead Sea.
Courtesy of Adi Torfstein
Morianes, ridges of debris left by past glaciers, near the Dead Sea.

Younger DryasThe most recent ice age that ended 11,500 years ago and an event that scientists refer to as part of “abrupt” climate change. Although at that time an ice age appeared to have halted on earth, the Younger Dryas returned conditions to nearly ice-age proportions. Slow warming following the event is what led to the past 10,000 years of relative climate stability that nurtured civilization as we know it.


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