Climate Change, Biotechnology and Modern Physics

MYP Unit Framework

Key Concept: SYSTEMS Related Concepts: Consequences. Evidence. Sustainability. Global Context: Globalisation and Sustainability (How can science help us address the most URGENT challenges facing humanity?) Statement of Inquiry: Scientific understanding of COMPLEX SYSTEMS — from Earth's climate to the human genome to the atomic nucleus — empowers us to address global challenges, but the APPLICATION of that knowledge raises PROFOUND ETHICAL QUESTIONS that science alone cannot answer.

Inquiry Questions

1. Climate Change — The Defining Challenge

The Greenhouse Effect — The Science

1. SOLAR RADIATION (shortwave) passes through the atmosphere and warms the Earth.
2. The Earth radiates heat back as INFRARED (longwave) radiation.
3. GREENHOUSE GASES (CO₂, CH₄, H₂O, N₂O) in the atmosphere ABSORB some of this outgoing infrared — trapping heat.
4. 'WITHOUT the natural greenhouse effect, Earth's average temperature would be −18°C — FROZEN. The greenhouse effect makes Earth HABITABLE. The PROBLEM is the ENHANCED greenhouse effect — humans adding EXTRA greenhouse gases, trapping TOO MUCH heat.'

The Evidence

The Human Causes

• Burning FOSSIL FUELS (coal, oil, gas) for energy — the LARGEST source. Deforestation (trees absorb CO₂ — cutting them RELEASES it). Agriculture (livestock — methane. Fertilisers — nitrous oxide). Industrial processes (cement production releases CO₂).

What Can Be Done?

• MITIGATION (reduce emissions): Shift to RENEWABLE ENERGY (solar, wind). Energy efficiency. Electrify transport. Reforestation. Carbon capture.
• ADAPTATION (cope with the changes already coming): Sea walls. Drought-resistant crops. Early warning systems for extreme weather.
• GEOENGINEERING (radical — controversial): Deliberately modifying Earth's climate system — e.g., injecting aerosols into the stratosphere to reflect sunlight. 'Risky. Unknown side effects. Who gets to decide for the ENTIRE PLANET?'

The Political Dimension

'The Paris Agreement (2015): 196 countries agreed to limit warming to WELL BELOW 2°C and pursue efforts to limit it to 1.5°C. But the commitments made so far (Nationally Determined Contributions) are INSUFFICIENT to meet these targets. There is a GAP between what science says is NECESSARY and what politics is willing to DELIVER.' The principle of 'Common But Differentiated Responsibilities' (CBDR) — rich countries who EMITTED MOST historically should bear GREATER responsibility.

2. Biotechnology — Rewriting the Code of Life

CRISPR-Cas9 — The Genetic Scissors

Discovered 2012 (Jennifer Doudna & Emmanuelle Charpentier — Nobel Prize 2020). 'CRISPR allows scientists to EDIT DNA — to CUT a specific gene and REPLACE it with a different sequence. It is CHEAP. It is PRECISE. It is REVOLUTIONARY.'

Applications

• Medicine: Correcting genetic diseases (sickle cell, cystic fibrosis). Engineering immune cells to ATTACK cancer. 'The first CRISPR-based therapies have been APPROVED.'
• Agriculture: Drought-resistant crops. Pest-resistant crops (reducing pesticide use).
• Conservation: Engineering corals to survive warmer oceans. 'De-extinction' — bringing back extinct species (e.g., the woolly mammoth).

The Ethical Questions

• SOMATIC editing (changes die with the individual — affects only that patient). Generally accepted.
• GERMLINE editing (changes passed to FUTURE GENERATIONS — affects the human gene pool). EXTREMELY CONTROVERSIAL. 'In 2018, a Chinese scientist announced he had created the world's first CRISPR-edited BABIES — twin girls, edited to be RESISTANT TO HIV. The scientific community CONDEMNED the action. He was sent to PRISON. The question remains: Should we edit the human germline — and if so, under WHAT CIRCUMSTANCES?'

The 'Designer Baby' Debate

'If we edit genes to eliminate DISEASE — most people agree that is good. But what about editing for ENHANCEMENT? Taller? Smarter? Stronger? A specific eye colour? Where does "therapy" END and "enhancement" BEGIN? And who gets ACCESS — only the wealthy? Biotechnology could REDUCE suffering — or it could ENTRENCH inequality.'

3. Modern Physics — The Atom and the Universe

Radioactivity

Discovered by Henri Becquerel (1896). Named by Marie Curie. Three types: Alpha (α) — helium nucleus. Least penetrating. Beta (β) — electron/positron. Moderate. Gamma (γ) — electromagnetic wave. MOST penetrating.

Half-Life: T₁/₂ = ln 2 / λ. Exponential decay.

'Radioactive isotopes are used in: MEDICINE (cancer radiotherapy, PET scans). ARCHAEOLOGY (carbon-14 dating). INDUSTRY (smoke detectors).'

Nuclear Energy — Fission

Heavy nucleus (Uranium-235) splits → HUGE energy release. Chain reaction. '1 kg of uranium-235 releases ~3 MILLION times more energy than 1 kg of coal.' Nuclear power: ZERO carbon emissions during operation. BUT: Radioactive WASTE (dangerous for thousands of years). Accidents (Chernobyl 1986, Fukushima 2011). Nuclear weapons proliferation.

Nuclear Fusion — The Holy Grail

Light nuclei (hydrogen) COMBINE → heavier nucleus + ENORMOUS energy. This is what powers the SUN. Advantages over fission: FUEL ABUNDANT (hydrogen from water). NO long-lived radioactive waste. NO risk of meltdown. 'The challenge: fusion requires temperatures of ~150 MILLION °C — hotter than the Sun's core. No material can contain it. Scientists use MAGNETIC CONFINEMENT. After decades of research, we are CLOSER than ever — but not yet there. Fusion is the "energy of the future — and always will be."'

Your Summative Assessment — The Interdisciplinary Investigation

Task: 'Science, Ethics and Action' Choose ONE of the following:

• Climate: Propose a CLIMATE ACTION PLAN for your school or community. Base it on SCIENTIFIC EVIDENCE. Address ECONOMIC and SOCIAL dimensions.
• Biotechnology: Write a POSITION PAPER on a specific application of genetic engineering. Argue for or against. Address ETHICAL concerns.
• Energy: Evaluate the role of NUCLEAR ENERGY in the transition to a carbon-neutral future. Weigh benefits against risks.

Your response must: Use SCIENTIFIC EVIDENCE. Acknowledge UNCERTAINTIES. Address ETHICAL DIMENSIONS. 'This is preparation for the MYP Sciences eAssessment — and for the interdisciplinary thinking the IB Diploma Programme demands.'

ATL Skills