Explained: How 2021 science Nobel Prizes impact our world

The science Nobel Prizes are often awarded for work that was done decades ago. This can be frustrating to scientists and in 2021, it led to disappointment for all those betting on Covid-related research and mRNA vaccine development. But there is an underlying logic to the awards; they are only given after it’s clear that the work was of extreme fundamental importance, and that can take a long time.

The physics and chemistry awards this year clearly highlighted environmental concerns. The physiology award was for some very elegant work that opened up a new understanding of biological sensory apparatus and nervous systems.

Here’s a brief explanation of the science behind the awards:

Physics: “A butterfly flaps its wings in Beijing, and you get rain instead of sunshine in New York” — This is probably the most evocative description of the chaos we call weather. The 2021 Nobel Prize in Physics went to a trio who created weather system models and found ways to spot patterns, and make predictions about weather and climate.

Syukuro Manabe and Klaus Hassel­mann were awarded half the prize money “for the physical modelling of Earth’s climate, quantifying variability and reliably predicting global warming”. The other half went to Giorgio Parisi “for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales”.

Chaos has a specific meaning in the mathematical sciences. It’s shorthand to describe “dynamic, non-linear” systems. In linear systems like a stereo amplifier, the output volume changes predictably as input voltage changes. Many non-linear systems are also predictable. For example, the force of gravity on two objects drops by three-fourths (not half) if the distance between the two objects is doubled.

Chaotic systems are both non-linear, and unpredictable. Very minor changes in input like the air currents caused by a butterfly flapping, can lead to huge unpredictable changes in output. What’s more, chaotic systems are as complex and unpredictable on tiny scales (like nuclear interactions) and on large scales (like planetary weather systems).

The 73-year-old Parisi from Sapienza University, Rome, worked out much of the maths for understanding chaos. Manabe (90-year-old, Princeton) and Hasselmann (89, Max Planck Institute for Meteorology, Hamburg) app­lied and refined much of the maths for weather and climate. Their models have accurately predicted climate change.

Chemistry: The 2021 Chem­istry Nobel went to Benjamin List and David MacMillan for their “development of a precise new tool for molecular construction: organocatalysis”. Catalysts are chemicals that induce and accelerate chemical reactions, without changing themselves. They tend to be metallic, or enzymes (our bodies use thousands of enzymes as catalysts to convert food, etc). Our cars use catalytic converters to convert some harmful exhaust gases into less harmful stuff.

Around 2000, List (53, Max-Planck-In­stitute for Coal Research, Mulheim an der Ruhr, Germany) and MacMillan (53, Prin­c­eton) separately discovered and resea­rched organic catalysts. Organic catalysts have a stable framework of carbon atoms, which can grab other chemical groups and help to build new molecules. These organic catalysts contain other non-metallic elements like carbon, oxygen, nitrogen, sulphur, phosphorus and tend to be environmentally friendly, and cheaply produced.

Interestingly organic catalysts can drive “asymmetric catalysis”. Two molecules may be chemically identical, but polarised differently, to be mirror images of each other. In areas like pharma research and solar energy, one of those molecules may be much more useful than the other.

Medicine: How do we feel temperature changes, pain and pressure before we respond? Our nervous system senses heat or cold and converts that to electrical impulses that tell our brain what to do. This depends on our sense of touch, and a complicated process of converting those signals within our nervous system. The 2021 Nobel for Physiology (or Medicine) went to David Julius and Ardem Patapoutian for their “discoveries of receptors for temperature and touch”.

Julius (65, University of California, San Francisco) used capsaicin, the compound that makes chillies “chilly”, in experiments to identify sensors in the nerve endings of the skin that respond to heat.

Patapoutian (55, Howard Hughes Medical Institute, Scripps Research, La Jolla, USA), experimented with putting pressure on pressure-sensitive cells (literally by poking cells with needles and micropipettes) to discover a novel class of sensors that respond to mechanical stimuli of skin and internal organs. Their research led to breakthroughs that increase the understanding of our nervous system and the ways in which we sense heat, cold, and mechanical stimuli. This is critical in our daily interactions with our environment and in pain treatment and management.