Future of Earth

- Introduction
-Greenhouse Effect
-Ice's role in the climate
-Water's role in the climate
-El Nino

Introduction

It is commonly believed that the Earth's weather is turning weird in the recent decades. Greenhouse effect leads to increase in the average temperature. Chlorofluorocarbons (CFCs) and other chemicals destroy ozone. Melting ice in the poles raises the sea level. Our planet is in danger. How can we save the worsening situation of the Earth?

What we have to do first is to understand how Earth's climate works and be aware of the millions of interactions that produce it. Thus we will know how humans can affect our atmosphere.

Greenhouse Effect

Greenhouse effect is a phenomenon in which the atmosphere prevents the heat radiated from the earth surface from escaping into the space. As heat is trapped in the Earth, the average temperature becomes higher than normal. Since this effect is worldwide, many people call this effect as the effect of global warming.

Energy from the sun drives the earth's weather and climate, and heats the earth's surface; in turn, the earth radiates energy back into space. Atmospheric greenhouse gases (water vapour, carbon dioxide, methane and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse. Without this natural "greenhouse effect," temperatures would be much lower than they are now, and life as known today would not be possible.

Why are greenhouse gas concentrations increasing? Scientists generally believe that the combustion of fossil fuels and other human activities are the primary reason for the increased concentration of carbon dioxide. Plant respiration and the decomposition of organic matter release more than 10 times the CO2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution with carbon dioxide absorbed by terrestrial vegetation and the oceans.

Rising global temperatures are expected to raise sea level, and change precipitation and other local climate conditions. Changing regional climate could alter forests, crop yields, and water supplies. It could also threaten human health, and harm birds, fish, and many types of ecosystems.

Ice's role in the climate

Large amounts of frozen water in the Greenland and Antarctic ice caps-as sea ice around the polar regions and mountain glaciers elsewhere-help create our climate by increasing the temperature contrast between polar regions and the mid latitudes.

Air over ice-covered polar regions grows colder than it would otherwise be, increasing the contrast between it and air farther from the poles. Strong cold-warm air contrasts supply more energy for storms than weak contrasts. But stronger winds caused by larger contrasts push more arctic air south and bring more warm air north, warming the polar regions.

The system creates a negative feedback. If polar regions warmed up enough in the future to melt some of the ice, more water would evaporate into the air, which could increase snowfall not only over the ocean, but also over nearby land.

Water's role in the climate

Water affects climate by taking up and releasing heat as it changes among its phases-vapour, liquid and ice. Both the amount of water that falls as precipitation and the amount available to be evaporated help determine a region's climate.

Oceans are a major player in climate. They hold large amounts of heat and move it around via global-scale currents. Since the oceans cool or warm slowly, they slow the temperature changes in the air above them. This why places near the ocean don't have temperature contrasts as large as places far inland. Summer winds are cool and winter winds are warm. Scientists refer to this slowing of temperature changes by the oceans as 'thermal inertia'.

El Nino

El Nino

Originally, the name El Nino (Spanish for "the Christ child") was coined in the late 1800s by fishermen along the coast of Peru to refer to a seasonal invasion of warm southward ocean current that displaced the north-flowing cold current in which they normally fished; typically this would happen around Christmas. Today, the term no longer refers to the local seasonal current shift but to part of a phenomenon known as El Nino-Southern Oscillation (ENSO), a continual but irregular cycle of shifts in ocean and atmospheric conditions that affect the globe. El Nino has come to refer to the more pronounced weather effects associated with anomalously warm sea surface temperatures interacting with the air above it in the eastern and central Pacific Ocean.

ENSO is an inter-annual perturbation of the climate system characterized by aperiodic weakening of the trade winds and warming of the surface layers in the equatorial Pacific Ocean every 4-7 years. The impacts of ENSO are felt worldwide through disruption of the atmospheric general circulation and associated global weather patterns. ENSO also affects the ecosystem dynamics in the Pacific Ocean, particularly the higher trophic levels of the food chain on which fisheries depend.

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