i. Geography 2050 Ch. 6

climate feedback

A ______ ______ enhances or diminishes climate change that has already been set in motion.

green economy

A ______ ______ is a sustainable economic system that has a small environmental impact and is based on renewable energy sources.

carbon footprint

A ______ ______ is the amount of greenhouse gases (particularly CO2) that any activity generates.

glacial period

A ______ _______ (or glacial) is an interval of cold climate within the Quaternary ice age.

55

About ______ million years ago, a long, slow cooling trend began.

99.9; 0.1

About ______% of Earth's carbon (65,500 billion metric tons) is stored in the lithosphere. The other ______% of Earth's carbon is found in the oceans, atmosphere, and biosphere.

Earth system model

An ______ ______ is a mathematical simulation of the behavior of the atmosphere, oceans, and biosphere that can be used to create long-term climate projections. Because of the complexity of the climate system, these models run some 80 million calculations per hour and billions of calculations over weeks and months, requiring the world's fastest supercomputers.

interglacial period

An ________ ________ (or interglacial) is an interval of warm climate that occurs between glacial periods.

ice-albedo positive feedback

An example of a destabilizing positive feedback in the climate system is the _____ _____ ______. When the temperature of the atmosphere increases, more snow and ice are melted. Bare ground and ice-free water absorb more solar energy than snow and ice and cause more warming, creating a positive feedback loop:

ninth

As a whole, the year 2012 stood as the ______ warmest in recorded history and the warmest ever for the United States.

solar forcing; volcanic forcing

As an example of a climate forcing factor, the Sun, if it were to shine more intensely, would force climate into a warmer state through _____ ______. Similarly, ______ ______ occurs when volcanoes erupt aerosols into the stratosphere, where they reflect sunlight and cool the planet's surface.

carbon cycle

Carbon atoms move among Earth's physical systems through the ______ _______.

carbonic acid

Carbon dioxide in the atmosphere combines with rainwater to form a weak acid called ______ ______.

chemical weathering

Carbonic acid in rainwater slowly dissolves the rocks over which it flows through the process of _______ ________ . This process releases calcium ions that rivers carry to the oceans.

orbital forcing

Changing Earth-Sun orbital geometry is a process that operates outside of, and is unaffected by, the climate system. Milankovitch cycles, therefore, constitute a climate forcing factor, referred to as _______ _______.

precipitation; increased; drier

Climate change is expected to change _______ patterns. Much of Canada and the northeastern United States are expected to receive _______ precipitation. The southwestern United States and the Mediterranean are expected to become _______.

Earth system models

Climatologists use ______ ______ ______ to develop predictions about how climate might respond to greenhouse gas forcing.

costly

Coping with increased droughts, floods, disease, sea-level rise, and shifting agricultural zones as a result of changing climate would be far more ______ than taking early steps to curb greenhouse gas emissions and preventing serious climate change.

Quaternary period

During the ice age of the last 2.6 million years, which geologists call the ________ ________, the climate has experienced a series of swings like a roller coaster, cycling back and forth between cold glacial periods and warm interglacial periods some 22 times.

together

During the past 800,000 years, atmospheric temperatures and CO2 concentrations have changed ______.

higher

Earth's average atmospheric temperature is ______ now than at any time in the last 1,500 years.

long-term trends, repeating cycles, and random anomalies

Earth's climate history can be reduced to three natural modes of change:

Antarctica

Given its accelerated rate of warming, the Arctic will continue to experience the greatest temperature shifts on the planet. ______ is also warming, but not as quickly, because it is relatively isolated by the Antarctic circumpolar current that flows around it.

C02; human activities

Given the evidence, the current warming trend can be explained only by the current increase in atmospheric _____ concentrations caused by ______ ______.

anthropogenic

Human emissions of CO2 and other greenhouse gases into the atmosphere are creating an _______ greenhouse effect: an enhancement of the natural greenhouse effect that is warming the planet.

warm; cool

If the Sun's total energy output were to increase, Earth would ______. If it decreased, Earth would ______.

postitive; negative

In this _____ feedback loop, it would get colder as more snow and ice reflected sunlight. But positive climate feedbacks do not go on forever. They are kept in check by ______ feedbacks that function to stabilize a changing system. We will return to the important role of climate forcing factors and feedbacks as we move through the remainder of this chapter.

Laurentide ice sheet

It would take a lot of fresh water to slow the ocean conveyor belt system. Where would such a massive influx of fresh water come from? That water probably came from the melting of the ________ ________ ________, the large ice sheet that covered much of North America during the most recent glacial period until about 12,000 years ago.

Milankovitch cycles

Milankovitch identified three periodic changes in Earth's orbital relationship to the Sun that led to changes in the timing and distribution of solar heating across Earth's surface. He argued that these small changes in Earth-Sun orbital geometry, now called ______ ______.

Younger Dryas

One example of nonlinear climate change was the ______ ______ cold period (named after a cold-loving plant called Dryas octopetala), which occurred between 12,900 and 11,600 years ago.

carbonate rocks

Organisms such as corals and clams build their shells from calcium carbonate ions, pulling carbon from seawater in the process. When they die, their shells form layers of sediments as well. Over time, these sediments and remnants of shells, cemented together, form ______ ______ such as limestone, locking away immense reserves of carbon in long-term storage in the lithosphere.

increasing

Scientists do know that the long-term average number of heat waves worldwide is _______. The "extra" heat waves are a result of Earth's changing atmosphere.

paleoclimates

Scientists who study Earth's ancient climates.

anthropogenic

Several key observations point to the ______ increase in atmospheric CO2 concentrations as the cause of the observed warming trend: Are people causing climate change? The rapid pace of atmospheric warming-mirrors the rapid pace of CO2 increase in the atmosphere. The nights are warming faster than the days. Greenhouse gases absorb outgoing terrestrial heat both day and night. The warming is most pronounced at night, however, when Earth is losing the heat it absorbed during the day. The lower stratosphere is cooling. This trend in the stratosphere is caused mainly by increased heat retention in the lower troposphere due to the increase of greenhouse gases.

climate change

Since 1880, the average temperature of the lower atmosphere has increased 0.83°C (1.5°F). The surface of the oceans has warmed by about 0.56°C (1°F) in the last century as well. These temperature trends are ______ ______.

warmer

Since the year 1976, every decade has been ______ than the previous one

short-term carbon cycle

The ______ ______ ______ ______ involves the movement of carbon among the oceans, the atmosphere, and the biosphere over spans of time from minutes to a few thousand years.

long-term carbon cycle

The ______ ______ ______ ______ involves the movement of carbon into and out of the lithosphere and takes millions of years to unfold.

ocean conveyer belt

The ______ ______ ______ is the global system of surface and deep ocean currents that transfers heat toward the poles. Its flow depends on differences in the buoyancy of ocean water caused by differences in its temperature and salinity. Colder, saltier water sinks to the depths and warmer, fresher water rises to the surface.

Cenozoic era

The ______ ______ began 66 million years ago. Early in that era, about 55 million years ago, the average global temperature was about 12°C (22°F) warmer than it is today.

Keeling curve

The ______ ______ is a graph showing the change in atmospheric CO2 concentrations since 1958

cryosphere

The ______ is the frozen portion of the hydrosphere, which includes glaciers and sea ice. We live in the atmosphere and are affected by it in a direct way, but the other systems are equally important in determining how Earth's climate functions.

climate forcing factors

The behavior of Earth's climate is controlled by forces that are unaffected by the climate system, called ______ ______ ______.

sea level; atmospheric circulation; extinctions

The following is a brief summary of some of the major anticipated changes to Earth's systems:

destabilizes

The ice-albedo positive feedback ______ the climate system and causes climate change by enhancing the warming trend that was already taking place.

Arctic; twice

The ice-albedo positive feedback is already well under way in the ______, which is warming at about ______ the global rate.

Eemian

The most recent of those warm periods was the ______ (also called the Sangamonian) interglacial, during which temperatures were about 1°C (1.8°F) above today's average.

photosynthetic organisms

The second way that carbon enters long-term storage in the lithosphere is through _______ ______, which include plants, algae, and certain types of bacteria. These organisms convert the Sun's radiant energy to chemical energy through the process of photosynthesis. During photosynthesis, they absorb carbon dioxide from the atmosphere, split the oxygen from it, and store the resulting carbon in their tissues.

radiation; cool; warm

Ultraviolet radiation _______ significantly during high sunspot activity. Fewer sunspots could ______ Earth, and more sunspots could _______ it.

Holocene epoch

We are currently in an interglacial called the _______ ______.

destabilizing

Whether natural or anthropogenic, any kind of climate change can be ______ for human societies

carbon- cap and traded

______ ______ ______ _______ systems allocate carbon "credits" to carbon producers, such as manufacturing companies. A company may purchase more carbon credits from other companies that have carbon credits to sell. Because the overall number of carbon credits is limited, the total carbon emissions of a country would be reduced.

internal feedbacks

______ ______ are important in amplifying the climate changes forced by Milankovitch cycles.

carbon taxes

______ ______ are seen by many as the most important legislation at the national level to reduce carbon emissions quickly and efficiently. Carbon emissions beyond a predetermined level could be taxed. This would provide an incentive to produce less carbon.

anomalous climate

______ ______ events occur randomly through time and are caused by climate forcings and feedbacks different from those that drive longer-term climate patterns.

human activity

______ ______ is increasing atmospheric CO2 concentrations by 2.5 parts per million (ppm) per year.

carbon dioxide

______ ______ is the most important contributor to the anthropogenic greenhouse effect.

ions; calcium carbonate

______ are atoms or molecules with electrical charges that readily react with other particles. Calcium ions combine with bicarbonate ions (HCO3−) in seawater to create chalky white ______ ______ (CaCO3) sediments, which are similar to the deposits that accumulate on faucets in homes with hard, mineral-rich water.

volcanoes

______ are climate wild cards.

sunspots

______ are dark and relatively cool regions that migrate across the surface of the Sun.

climate change

________ ________ occurs when the long-term average of any given meteorological variable, such as temperature or precipitation, changes. Individual extreme weather events do not change the long-term average.

lithosphere; atmosphere

eople have greatly accelerated the transfer of carbon from the _______ to the ______ by burning fossil fuels.

solar irradiance

he amount of solar energy reaching Earth, or ______ _____, has been measured precisely since 1978 by satellites orbiting above the distorting effects of Earth's atmosphere. During that time, only small variations in the intensity of the Sun's output have been detected.