Climate & the Living Earth

Weather is the short-term condition of the atmosphere. Climate is the long-term pattern of weather measured across decades.

Temperature, precipitation, wind, humidity, cloud, and air pressure describe weather. A thunderstorm this afternoon is weather. The usual range of winter temperatures and snowfall across many years is climate.

Climate is not one average. It includes typical conditions, seasonal cycles, variation, and the frequency of extremes. A warming climate can still produce cold days; the distribution is shifting, not deleting winter overnight.

Meteorologists forecast weather using current observations and physical models. Climatologists study long records, patterns, causes, and future scenarios. Both use evidence, but they ask different time-scale questions.

One record-hot day does not prove climate change by itself. A sustained pattern across many locations and indicators—temperature, ocean heat, ice, sea level, seasons—provides stronger evidence.

Two places at similar latitude can have very different climates because oceans, winds, elevation, and mountains redistribute heat and moisture.

Latitude affects solar angle and day length. Near the Equator, sunlight is more direct; toward the poles, the same energy spreads over a larger area. Earth’s tilt creates seasons by changing solar angle and daylight through the year.

Large bodies of water heat and cool slowly, reducing temperature range near coasts. Ocean currents move heat. Prevailing winds and air masses carry temperature and moisture from their source regions.

Temperature usually decreases with elevation in the lower atmosphere. Mountains force air upward, causing cooling and precipitation on the windward side. Descending air on the leeward side warms and dries, producing a rain shadow.

Vancouver and Winnipeg show the combined effect. Vancouver’s Pacific setting creates milder winters and a smaller annual temperature range. Inland Winnipeg experiences stronger continental heating and cooling.

A climate graph combines average monthly temperature and precipitation. The shape of the year helps identify climate controls and regions.

Temperature is commonly shown with a line and read from one vertical axis. Precipitation is shown with bars and read from another. Always check units and axes before comparing.

Annual temperature range is the warmest monthly average minus the coldest. Total annual precipitation is the sum of monthly values. Seasonal distribution matters: two places can receive the same annual total but at different times.

Broad climate regions include tropical, dry, temperate, continental, and polar climates, with important subtypes. Boundaries are transitions, not walls. Elevation can create mountain climates that differ from surrounding lowlands.

A mystery graph is evidence. A small temperature range and year-round rain may suggest a maritime tropical setting. A huge range and summer precipitation may suggest a continental interior. The graph narrows possibilities; a locator map confirms.

Natural vegetation reflects climate, soil, water, landforms, disturbance, and time. Change one part of the system and the boundaries can shift.

Tropical forests grow where warmth and moisture are abundant. Grasslands often occur where rainfall is seasonal or insufficient for dense forest. Boreal forest tolerates long cold winters. Tundra supports low plants where cold and permafrost restrict roots and growth.

Fire, insects, storms, grazing, and succession naturally change vegetation. Human activities—clearing, farming, introduced species, pollution, and urban growth—can accelerate or redirect change.

Human greenhouse-gas emissions are warming Earth and changing climate patterns. Evidence includes rising global temperatures, ocean heat, glacier and ice loss, sea-level rise, and changes in seasonal timing. Impacts differ by region.

In Canada, warming is especially rapid in the North. Permafrost thaw affects land, buildings, roads, ecosystems, and travel. Indigenous communities hold detailed land-based knowledge, but effects and priorities vary among nations and places.

Climate action includes mitigation—reducing the causes—and adaptation—reducing harm from changes already occurring. These are partners, not substitutes.

MAP EVIDENCEWarming is not spatially even

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