Biology · 9th Grade · Ecology and Global Systems · Weeks 28-36

Climate Change: Causes and Impacts

Evaluating the biological impacts of rising global temperatures, ocean acidification, and extreme weather events.

• Common Core State Standards
• HS-ESS3-5
• HS-LS2-7

About This Topic

Current climate change is driven primarily by the burning of fossil fuels, deforestation, and agriculture, which release greenhouse gases (CO2, methane, nitrous oxide) that trap additional solar energy in the atmosphere and raise global average temperatures. In 9th grade biology, students evaluate the evidence for this scientific consensus, including atmospheric CO2 records, global temperature anomalies, glacial ice core data, and documented changes in biological systems. This topic aligns with HS-ESS3-5 and HS-LS2-7 and serves as a capstone for the ecology unit, applying the biogeochemical cycle concepts students just studied to a real-world systems-level problem.

Climate change affects living systems in multiple, interacting ways. Phenological shifts, changes in the timing of seasonal events like flowering, migration, and breeding, disrupt ecological relationships that evolved over millennia. Species distributions are shifting poleward and toward higher elevations. Ocean acidification, caused by increased CO2 absorption, threatens marine organisms that build calcium carbonate shells. Habitat fragmentation reduces species' ability to track shifting climate zones, compounding extinction risk.

Active learning is essential for this topic because students bring prior beliefs, media exposure, and sometimes family-based attitudes that must be engaged with evidence rather than avoided. Data analysis activities that put students in the role of scientific evaluators build both content knowledge and the confidence to reason about complex, socially contested environmental issues.

Key Questions

1. Explain the scientific consensus on the causes of current climate change.
2. Analyze how climate change alters the timing of biological events (phenology).
3. Predict the risks of climate-induced habitat fragmentation and species migration.

Learning Objectives

• Analyze data sets, such as ice core samples or temperature anomaly charts, to identify trends supporting the scientific consensus on anthropogenic climate change.
• Evaluate the impact of rising global temperatures on the phenology of at least two different species, citing specific examples of disrupted ecological interactions.
• Predict the consequences of ocean acidification on marine organisms with calcium carbonate structures, such as coral reefs or shellfish.
• Synthesize information to explain how habitat fragmentation exacerbates the risks faced by species attempting to migrate due to climate change.

Before You Start

Biogeochemical Cycles

Why: Students need to understand the movement of carbon, nitrogen, and water through Earth's systems to grasp how human activities disrupt these cycles and contribute to climate change.

Ecosystem Structure and Function

Why: Understanding food webs, energy flow, and species interactions is essential for analyzing the cascading impacts of climate change on ecosystems.

Key Vocabulary

Anthropogenic	Originating from human activity, particularly in the context of environmental change. This term is central to understanding the causes of current climate change.
Phenology	The study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life. Changes in phenology are a key biological impact of climate change.
Ocean Acidification	The ongoing decrease in the pH of the Earth's oceans, caused by the uptake of anthropogenic carbon dioxide from the atmosphere. This process directly harms marine life.
Habitat Fragmentation	The process by which large, continuous habitats are broken up into smaller, isolated patches. This makes it harder for species to survive and adapt to changing conditions.
Climate Feedback Loop	A process that occurs as a result of a change in one part of a system, which in turn affects the system, leading to either an amplification or reduction of the original change. These loops can accelerate climate change.

Watch Out for These Misconceptions

Common Misconception

Weather and climate are the same thing.

What to Teach Instead

Weather describes short-term atmospheric conditions at a specific place and time. Climate describes long-term average atmospheric patterns for a region over decades. Climate change refers to persistent shifts in these long-term averages. Drawing an explicit timeline contrast between a single day's weather and a 30-year climate normal helps students keep these conceptually distinct and prevents them from using cold winter days as counter-evidence for warming trends.

Common Misconception

Because CO2 is naturally present in the atmosphere, human emissions are not a problem.

What to Teach Instead

While CO2 is a natural component of the carbon cycle, human activities have raised atmospheric CO2 from approximately 280 ppm before industrialization to over 420 ppm today, faster than the carbon cycle's natural feedback mechanisms can buffer. The issue is the rate and scale of the change, not the presence of CO2 itself. Graphing ice core CO2 data alongside the Keeling Curve makes the anomalous nature of current concentrations visually clear.

Common Misconception

There is significant scientific disagreement about whether climate change is human-caused.

What to Teach Instead

Multiple independent lines of evidence, from ice cores to ocean heat content to biological observations, converge on the same conclusion. Studies of the peer-reviewed literature consistently find that over 97% of actively publishing climate scientists endorse the consensus that current warming is primarily human-caused. The Jigsaw Evidence activity helps students understand what it means for multiple independent datasets to converge on one conclusion.

Active Learning Ideas

Jigsaw: Multiple Lines of Evidence

Small groups each analyze one dataset (Keeling Curve CO2 record, global temperature anomaly graph, Arctic sea ice extent trend, phenological timing shifts in migratory birds). Each group creates a one-page visual summary, then groups rotate in a jigsaw format to brief each other. The class assembles all four lines of evidence into a unified argument about climate change.

60 min·Small Groups

Case Study Analysis: Phenological Mismatch

Pairs analyze published data showing the growing mismatch between peak caterpillar emergence timing and great tit nesting and hatching timing in Europe as spring warming accelerates. They diagram how the mismatch reduces nestling survival, then identify two US species relationships where similar phenological mismatches have been documented and predict the likely population-level consequences.

40 min·Pairs

Collaborative Mapping: Species Range Shifts

Small groups receive projected range maps for three species (American pika, staghorn coral, polar bear) under current conditions and projected 2 degrees Celsius and 4 degrees Celsius warming scenarios. They annotate the maps with specific barriers preventing migration and propose one feasible conservation action for each species, citing the evidence that supports their recommendation.

45 min·Small Groups

Gallery Walk: Claim-Evidence-Reasoning Practice

Seven stations each display one common climate change misconception (such as 'CO2 is natural so it cannot be a problem' or 'scientists disagree about climate change'). Students write a CER response at each station using specific scientific evidence, then compare responses with a partner to refine the quality of evidence and reasoning before a whole-class share-out.

50 min·Pairs

Real-World Connections

• Marine biologists working with NOAA are studying the impact of ocean acidification on oyster farms along the Gulf Coast, seeking ways to mitigate economic losses and protect a vital food source.
• Ecologists in the U.S. National Parks are tracking shifts in animal migration patterns and plant blooming times to understand how species are responding to warming temperatures, informing conservation strategies for areas like Yellowstone.
• Climate scientists at NASA's Goddard Institute for Space Studies analyze satellite data and global temperature records to refine climate models and predict future extreme weather events, such as increased hurricane intensity in the Atlantic.

Assessment Ideas

Quick Check

Provide students with three short data summaries: one showing rising CO2 levels, one showing increasing global average temperatures, and one showing a shift in a specific species' migration timing. Ask students to write one sentence explaining the connection between these data sets.

Discussion Prompt

Pose the question: 'Imagine you are a park ranger in a region experiencing significant climate change. What are two specific challenges you might face related to species survival and habitat management, and how would you use your understanding of climate impacts to address them?'

Exit Ticket

On an index card, have students define 'phenology' in their own words and then list one example of a phenological shift and its potential consequence for an ecosystem.

Frequently Asked Questions

What is the scientific consensus on the causes of current climate change?

The scientific consensus, endorsed by every major scientific organization worldwide, is that current climate change is driven primarily by human activities, especially fossil fuel combustion and deforestation. These activities have raised atmospheric CO2 from about 280 ppm before industrialization to over 420 ppm today. This conclusion rests on multiple independent lines of evidence including ice core records, atmospheric measurements, ocean heat content data, and biological observations.

How does climate change alter the timing of biological events?

Phenology is the study of the timing of seasonal biological events. Many species have evolved their timing of flowering, migration, hatching, and breeding in response to temperature and day-length cues. As spring arrives earlier with warming temperatures, these cues shift, but not all species shift at the same rate. When a migratory bird arrives on its breeding grounds to find the insect emergence peak it needs to feed nestlings has already passed, both the bird and the insects are affected.

What are the risks of climate-induced habitat fragmentation for species migration?

As climate zones shift poleward and to higher elevations, species must migrate to track suitable habitat. But landscapes fragmented by roads, cities, and agriculture block movement corridors. Species that cannot move fast enough, whether due to slow dispersal rates or physical barriers, face local extinction as their existing habitat becomes climatically unsuitable. Small isolated populations are also more vulnerable to inbreeding and disease, compounding the extinction risk.

How does active learning support evidence-based reasoning about climate change?

Data analysis activities are especially valuable for climate topics because they give students direct experience evaluating evidence rather than just exposure to conclusions. When students graph real atmospheric CO2 records, analyze phenological timing data, or map species range shifts, they build confidence in reasoning from evidence. The CER framework applied during gallery walk activities develops the specific skill of distinguishing scientific claims from opinion, which serves students well beyond the biology classroom.