---
title: "Earth's climate has a history"
course: "ENVR 200 · Climate change, explained"
unit: "How the climate system works"
lesson: 3 of 19
source: https://open.maestrocollege.edu/climate-change-explained/earth-s-climate-has-a-history
publisher: Maestro College
---

# Earth's climate has a history

Lesson 3 of 19 in **Climate change, explained** (ENVR 200), unit "How the climate system works". An open lesson from Maestro College.

## What the learner will be able to do
- Trace major shifts in Earth's climate across deep time, including glacial and interglacial periods, and recognize the slow natural trend of the last several thousand years as one of gradual cooling.
- Identify ice ages and interglacials as natural climate states that pre-date any human influence.
- Identify the main natural causes of past climate shifts - orbital cycles, large volcanic events, and solar variation - at a plain-language level, accounting for all three rather than orbital cycles alone.

## Teaching notes
Natural drivers only; human drivers are set aside until u1l6/u1l8. State the recent natural trend as gradual cooling, but defer 'fossil fuels reversed it' to u1l6/u1l8. Chemical weathering and organic-matter burial are out of scope.

## Course teaching approach
- Start from a real-world problem, then introduce the concept as the solution.
- Keep it true beginner level, hands-on, a little gamified. The learner should feel they are winning.
- Balance explanation, demonstration and practice. No copy-paste exercises: give small story-based tasks.
- End with one fun closed question about the topic.

## How to use this document
You are acting as a tutor for a learner on Maestro Open. Teach from this document, one small step at a time. Ask the learner to try things, wait for their answer, then give feedback. Keep it beginner-friendly. If the lesson involves code or spreadsheets and you cannot run them, ask the learner to try it on their own computer and paste the result back. Do not award grades, credit or certificates.

## When the lesson is done
The lesson is complete only when the learner has shown they can do every outcome listed above. Check each one with a small task or question; if an answer is wrong, explain and let them try again before moving on.
When every outcome is covered:
1. Say clearly: "Lesson 3 complete: Earth's climate has a history."
2. Give a two-line recap of what they learned.
3. Name the next lesson, "How scientists read the past" (lesson 4 of 19), and give the learner its link: https://open.maestrocollege.edu/climate-change-explained/how-scientists-read-the-past.md. Tell them to paste that page into this chat, or fetch it yourself if you can open links, then start it the same way. Do not start teaching the next lesson's topic until the learner has it.

Previous lesson: Weather is not climate
Next lesson: How scientists read the past