Unit 2: Climate Due 9/17/2015

Climate vs. Weather Climate and Weather are not the same thing. Weather is the condition of the atmosphere in one place over a short period of time. Climate is the average weather conditions in a specific location over many years. Climate is affected by the Earth’s tilt towards the sun. Axis is currently tilted at 23.5 degrees Not all places receive the same amount of sunlight – less sunlight means cooler temperatures Generally cooler at night that during the day

Seasons Earth makes on revolution around the sun ever 365 days – year. Because the Earth’s revolution and axis tilt affects the amount of sunlight it receives, we have seasons. Seasons are reversed in Southern Hemisphere. Two equinoxes a year – the Sun is directly over the Equator Equal day and night – Vernal (Spring) and Autumnal (Fall) When Sun is over the Tropic of Cancer – beginning of Summer When Sun is over the Tropic of Capricorn – beginning of Winter Remember this is reversed in South Hemisphere

Midnight sun Polar phenomenon where six months of the year are either dark or daylight. Midnight sun – daylight or dusky Experience by some people in North America (Alaska and Canada) and Northern Europe (Sweden, Norway, Finland and Russia

Greenhouse effect Not all of the sun’s rays get through the atmosphere Would be to hot to survive Radiation would be toxic 50% makes it surface It is reflected and absorbed by the ‘greenhouse gases’ – methane, carbon dioxide, water vapor – Regulates earth temperature Would be below freezing if not Balance is essential to sustain life

Latitude and Climate The Earth-Sun relationship creates predictable and reliable climate bands around the Earth. The Koppen System  Tropical Humid Seasonally humid Dry Semiarid Desert Warm Mid Latitude/Mild Humid Mediterranean Marine west coast Cold Mid Latitudes/Snow Humid Continental Subartic Polar Ice Cap Tundra Elevation affects climate – the higher up, the cooler the climate

Koppen’s Climate Bands/Regions Tropical Climates Average is 80 Wet/Dry Seasons – agriculture has to mirror these seasons Dry Climates Semi-arid –steppes (high, dry plateaus, moderate rain Dry – desert 10 inches or less of rain Mid latitude Forests Grassland Most hospitable to human inhabitance Most populated regions tend to mid/high latitude High Latitude/Polar Tundras – flat plains that experience permafrost (soil that is always frozen) Ice caps are covered in ice that is about 2 miles thick.

Wind and Ocean Currents Wind is very important to climate Distributes energy around the planet Can bring in warm or cold air (think fronts in weather) Ocean currents also distribute energy – distribute warm and cold water geographically Prevailing winds – consistent wind patterns Have historically helped with navigation Coriolis effect – earth’s rotation causes winds to blow diagonally instead of in straight due directions. Doldrums – patches of very little wind movement – very calm air – usually found around the Equator

Wind and Current on Weather Driven by temperature, condensation causes precipitation – rain, snow, sleet, or hail. Storms are created when fronts (warm and cold air patterns) meet. Tropical systems (hurricanes and typhoons) develop along current systems, and are affected by prevailing winds (can predict where they will affect land) El Nino – periodic change in Pacific Ocean currents and water temperatures – results in high precipitation in the Western Hemisphere, and droughts in the East.

Mountains and Climate Windward – side of mountain facing wind…generally receives precipitation. Leeward – opposite side…much drier. Often find deserts on the leeward sides of mountains.

Biomes Plant life covers nearly entire land surface of the earth. Vegetation includes four major groups (called biomes)… Forest Savanna Grassland Desert

Climate Change Any change in factors used to measure and track climate The Argument: The Earth goes through natural cycles where it has cooled and reheated – the recent change is not only expected, but part of the Earth’s renewal process. The growing presence of pollution, fossil fuel emissions causing greenhouse gases to rise, and deforestation is causing the Earth’s temperature to rise dramatically. The Reality: Water levels are rising. The Earth is warming. Severe weather patterns (heat waves, blizzards, tropical systems) are becoming less predictable and more erratic in their occurrences.