Weather, Climate and Ecosystems

One day is not the climate

This theme joins two things that seem separate, weather and climate on one side and ecosystems on the other. They belong together because you read both of them by refusing the same two mistakes. The first mistake is treating a single event as the pattern. Weather is what the atmosphere is doing right now, over hours or days: this shower, today wind, the cold snap this week. Climate is the average of that weather over a long time, taken across about thirty years. They are not two words for the same thing. So a cold week tells you about the weather, not the climate. Climate change means the long-term average shifting, and a single chilly day neither proves nor disproves it. To see climate you have to step back from the events and look at the average. The UK climate has a settled character, and it comes from where the UK sits. Surrounded by sea, in the middle latitudes, and reached by moist winds from the south-west, the UK is mild and wet, without great extremes. Those fixed facts of position are why the pattern holds year after year. The second mistake is treating a part of a system as if it stood alone. An ecosystem is all the living things in a place together with the non-living conditions, soil, water, climate, all depending on one another. Change one part, remove a plant, warm the water, and the change ripples through the rest. That is the link between the two halves. Climate is the pattern behind the day, and an ecosystem is a web where nothing stands alone. Both reward stepping back to see the whole rather than the single piece. Carry two questions through everything that follows: am I looking at a single event or the long-term pattern, and am I treating this part as isolated or as connected?

Words for this theme

Five terms, each defined by what it is. The first three are the climate half, the last two the ecosystem half.

Tap the two about climate

Tap the TWO statements that describe climate, the long-term pattern, rather than the weather of a single moment.

• On average this region is mild and wet, with the wettest months in autumn, measured across many years
• Over recent decades the average temperature here has been slowly rising
• It is raining heavily this afternoon and the wind is strong
• This week has been colder than usual for the time of year

Why one cold day proves nothing

Someone points to a single very cold day and says it disproves climate change. Why are they mistaken?

• A single cold day is weather, and climate change is about the long-term average, which can only be seen across many years, so one day cannot settle it either way
• Because it is never actually cold anywhere any more
• Because weather is not real, only climate is
• Because climate change only happens in summer

Plot the summer peak

A hypothetical UK weather station, shown as an illustrative example rather than real data. The graph shows average monthly temperature in degrees Celsius across the year, which is a climate graph because it shows the average pattern, not one day. Plot month 7, where the average was 17, and month 8, where it was 17, so the summer peak shows.

Weather against climate

The same place, described two ways. One is a moment; the other is the long-run pattern.

Match each term to what it means

Two that follow from the theme

Select the TWO statements that follow from reading these systems as patterns and webs rather than single pieces.

• To judge the climate of a place you need weather records from many years, not one
• Removing one species from an ecosystem can affect others that depended on it
• One unusually warm day is enough to prove the climate has changed
• Each plant and animal in an ecosystem lives independently of the others

Reading a climate graph and a food web

Two quick methods, one for each half of the theme. For a climate graph, read the pattern, not a point. A climate graph shows average temperature and rainfall by month. Look for the shape: which months are warmest, which are wettest, and how big the gap between summer and winter is. That shape is the climate, and describing it is what earns marks, not reading off a single value. Name the UK pattern from its causes. The UK is mild and wet because the sea around it keeps temperatures even, its middle-latitude position keeps it from extremes, and moist south-westerly winds bring rain. Linking the pattern to those fixed causes is stronger than just describing it. For an ecosystem, follow the connections. Producers, usually plants, make food using sunlight; consumers eat them; decomposers break down what dies and return nutrients to the soil. Each depends on the others, so trace what a change would do along those links. Say what a disturbance would ripple into. If a question changes one part, warms the water, clears the trees, do not stop at that part. Follow the effect through the web to the parts that depended on it. Two habits cost marks. The first is treating a single warm or cold spell as the climate. The second is describing an ecosystem as a list of separate living things instead of a connected web.

Order the flow through an ecosystem

Put these stages of how energy and nutrients move through an ecosystem into a sensible order.

• Energy arrives from the Sun
• Plants, the producers, use it to make their own food
• Animals, the consumers, eat the plants or each other
• Living things die and their remains fall to the ground
• Decomposers break the remains down
• Nutrients return to the soil for plants to use again

Build the two-part rule

This is the idea that joins the two halves of the theme. Assemble it.

The weather and ecosystems quick-fire

Five questions on the two halves of the theme. Three lives.

One change, rippling through

Here is interdependence worked through on one example. The ecosystem is a tropical rainforest, named only as an example of the kind of global ecosystem studied, and no figures are invented for it. In a rainforest the tall trees form a dense canopy of leaves high above the ground. Those trees are producers: they make food using sunlight, and their leaves feed insects, their fruit feeds birds and mammals, and their roots hold the thin soil in place. Below them, little light reaches the floor, and the plants and animals there are suited to that shade and shelter. Now follow a single change. Suppose an area of those tall trees is cleared. The obvious loss is the trees themselves, but the point of interdependence is what follows. Sunlight now floods the floor, changing which plants can grow. The animals that fed on the fruit and lived in the canopy lose both food and home. Rain that the canopy used to intercept now hits the bare soil directly, and with the roots gone the thin soil is washed away, so even if trees were replanted the ground is poorer. One change, and it reached the light, the animals, the rain and the soil. None of those parts was really separate from the trees; they only looked separate until something moved. That is the habit the ecosystem half of this theme rewards. Do not stop at the part that changed. Trace the change along the connections to everything that depended on it.

Complete the climate facts

What the atmosphere is doing over hours or days, such as todays rain, is the _____. The average of that over about thirty years is the _____. A long-term shift in that average, which scientists link largely to human activity, is _____. To see it you have to step back from single events and look at the long-run average.

Three claims to sort out

Three statements about this theme. In each case pick the response that reads the system correctly.

• A student writes that a heatwave lasting a week proves the climate of their region has changed. How should this be corrected?
• A question asks what would happen if a plant that many insects feed on were removed from an ecosystem. What is the best answer?
• A student describes the UK climate as mild and wet but cannot say why. What would strengthen the answer?

Explain how to read this theme

A student in the year below keeps mixing up weather and climate and describes ecosystems as lists of separate creatures. Explain how to read both halves of this theme correctly.

• Explain the difference between weather and climate, including the timescales
• Explain what climate change is, and why a single cold or warm day does not show it
• Explain why the UK climate is mild and wet, linking it to the causes
• Explain what an ecosystem is and what interdependence means
• Explain why removing one part of an ecosystem affects the others
• Finish with the one habit that reads both halves of the theme correctly