Combating climate change will entail a true fusion of human skills:  The conceptual innovation of net zero, the engineering ingenuity of decarbonized industries, the physical graft of building smart cities.  Across the world, hands and minds must unite like never before to prevent the catastrophic impacts of our over-heating planet.

How much easier could our challenges be – how much more realistic our goals – if our efforts were embellished by a new ally, in the shape of ‘quantum computing’?

We are about to discover the answer.

You have probably encountered the term quantum computing, albeit in passing, and maybe paid no great heed.  Unless you work in the field, it may so far have had little consequence for your daily life.  But if all goes to plan, that might be about to change.

Quantum computing is best envisaged as a multidisciplinary technology, one which merges cutting-edge mathematics, physics and computer science to design processors of unprecedented power and speed.

The technology exploits so-called quantum mechanical effects such as superposition and entanglement – physical behaviors unique to particles at the subatomic level – to solve problems dramatically faster than conventional – (micro)transistor-powered – computers.

And it’s that speed that is the key to quantum’s potential.  Quantum technology is estimated to be 158 million times faster than the most powerful supercomputer, capable of doing something in 200 seconds that it would take a modern supercomputer over 10,000 years to accomplish.[1]

10,000-year sum cracked in seconds

So how does it work?  Traditional computing relies on binary transistors representing either 1 or 0 (yes or no; on or off) in a given query.  Quantum computing, in contrast, draws on the power of quantum bits, or ‘qubits’, which can represent both 1 and 0 at the same time – a superposition of states.

This multiplicity of states makes it possible for a quantum computer with just 30 qubits, for example, to perform 10 billion floating-point operations per second.[2]  Think of the potential leaps forward for complex and costly research areas such as aerodynamic modeling, drug development, supply chain optimization, gene therapy and more.

Quantum processors can make assumptions about a particle by measuring a related one within a closely-linked system – a feature known as entanglement.  For example, one qubit’s clockwise spin must be matched by a corresponding qubit’s counterclockwise spin.  Measuring a qubit’s quantum state causes its wavefunction to collapse, correlating its state in relation to other qubits regardless of distance, and allowing vastly complicated sums to be resolved almost instantly.  In this way, the power of quantum computing increases exponentially in line with the number of qubits.

The term ‘quantum computing’ itself is a little misleading, conjuring up images of conventional whirring desktop PCs and dusty keyboards.  The reality is quantum and conventional computing are two parallel worlds with some similarities, but many differences.  Three of the most important ones are:

  • Programming language: Quantum computing does not have its own programming code and requires the development and implementation of very specific algorithms.
  • Functionality: Quantum computers are not intended for widespread, everyday use, unlike today’s personal computers (PC).  They are so complex they can only be used in the corporate, scientific and technological fields.
  • Architecture: Quantum computers have a simpler architecture than conventional computers and they have no memory or processor.  The equipment that makes it run consists solely of a set of qubits.

As quantum computing evolves it will have revolutionary applications across three broad areas – optimization, machine learning, and simulating physical or molecular chemical systems – all with outcomes way beyond the capacity of even the fastest and most powerful of today’s ‘supercomputers’.[3]

  • Optimization: Improvements within industries are ordinarily hard to predict and expensive to trial, but quantum computing can juggle multiple variables to devise unexpected efficiencies:  Reduced material costs, streamlined logistics, product performance enhancements, and ultimately increased ROI.  Quantum computing can transform good into great, with minimal effort and risk.
  • Simulation: Traditional computers cannot, with efficiency or accuracy, calculate the quality of interaction between two complex properties.  By simulating materials and running through near-limitless iterations, quantum computing automates a previously hands-on and time-consuming process.  Shedding light on the interactions between molecules will help usher in a new breed of drugs, materials, and chemicals.
  • Machine learning: Quantum-enhanced machine learning (algorithms analyzing classical data on a quantum computer) will deliver extra value to businesses and industries already familiar with conventional machine learning.  New quantum tools will offer immeasurably greater computational speed and data storage capacity.

So, given these huge benefits, where are all our quantum computers, and why have we not already retired their sluggish microchipped forebears?  After all, quantum computing breakthroughs are reported almost weekly; the sector is acting like a brain magnet for our youngest and brightest minds; and quantum startups are being enthusiastically funded around the world.  Why the delay?

Despite widespread enthusiasm and optimism, the technology is still under development.  Our current generation of NISQ (Noisy Intermediate Scale Quantum) devices are prone to errors in the quality and stability of qubits, a state known as incoherence, which limits their performance.

However, with the technology constantly being honed, a true quantum revolution might arrive sooner than we think.  Current trends indicate the first generation of fault-tolerant quantum computers (those with logical error rates at arbitrarily low levels) could hit the market by the end of the 2020s.  That is when the scope of its potential for counteracting climate change will come into clearer focus.

Energizing industry, capturing carbon

Satisfying net-zero emission targets is beginning to look almost impossible using today’s technology.  Unfortunately, even if fully adhered to, pledges made at the 2021 United Nations Climate Change Conference (COP26) will still translate to a 1.7°C to 1.8°C global temperature rise by 2050, far exceeding the 1.5°C limit considered necessary for avoiding the worst impacts of climate change.[4]

The enormous potential of quantum computing, on the other hand, could upend these bleak forecasts.  Quantum computing, by some estimates, could drive the development of technologies capable of cutting carbon output by 7+ gigatons annually by 2035 – suddenly making 1.5°C a viable target once more.

Quantum computing could make a significant contribution either by spurring the proliferation of technologies most in need of scaling-up, or by greening emission-intensive sectors once thought impervious to intervention.  What specifically can we look forward to in the coming years as the quantum computing vision unfolds?

Electrification:  Batteries of vast capacity and durability are vital for the grid-scale storage of variable energy sources such as wind and solar.  However, improvement rates in battery energy density have slowed sharply, from a 50% density improvement between 2011 and 2016 to an estimated 17% increase between 2020 and 2025.  Quantum computing, by allowing a more detailed analysis of electrolyte complex formation, could indicate a replacement material for cathodes/anodes and eradicate the need for battery separators.

Halving the cost of grid-scale storage could increase solar use by 60% across Europe by 2050, according to one study.[5]  Meanwhile, batteries of 50% higher energy density will accelerate the business case for their widespread adoption in heavy goods vehicles.

Agriculture:  Low methane feed additives could cut the current 7.9 gigatons of CO2 emitted annually from cattle by 90%.  Quantum computing could assist in the development of an anti-methane vaccine, one that helps antibodies attach themselves to the right microbes in the hostile environment of a bovine gut.

Carbon capture:  Extracting and trapping carbon from the air works in principle but is prohibitively expensive at present.  Quantum computing is primed to drastically cut costs for both ‘point-source capture’ and ‘direct-air capture’ technologies.

Under the point-source method, CO2 is captured directly from intense pollution sources such as industrial furnaces.  Quantum computing will model optimum molecular structures for multiphase solvents integral to the process, increasing capture efficiency across a range of CO2 sources and cutting costs by up to a half.

Under the direct-air method, CO2 is captured straight from the atmosphere in a system both stubbornly expensive and energy-intensive.  Quantum computing will help design novel absorbents such as metal organic frameworks (MOF), which can process CO2 far more efficiently than today’s comparable technology.

Power and fuel:  Current crystalline silicon solar cells operate at about 20% efficiency.  Quantum computing dangles the promise of 40% efficient solar cells based on perovskite crystal structures.  Perovskite lacks durability and is toxic in some combinations.  Quantum computers, by simulating perovskite structures in multiple permutations using different base atoms, will design long-lasting and nontoxic solutions, potentially halving the cost of solar power.

Ammonia, costly and energy-intensive to produce, presently accounts for just 2% of the world’s energy use.  Nitrogenase bioelectrocatalysis offers a tantalizing glimpse of how ammonia could be produced cleanly, at a fraction of its current price.  The process artificially replicates ‘nitrogen fixation’, by which plants absorb nitrogen directly from the air and convert it into ammonia.  Nitrogenase works at room temperature and at 1 bar pressure, eclipsing the efficiency of the current 500°C Haber-Bosch method.  The technology is not yet ready for scaling-up, but quantum computing is expected to rapidly resolve issues around enzyme stability and low rates of output.  Apart from cutting the CO2 burden of the fertilizer industry, the estimated 67% cost reduction could hasten by a decade ammonia’s widespread adoption as a shipping fuel.[6]

High cost has also been an inhibiting factor for green hydrogen, but refining the process of electrolysis could finally help it reach commercial parity with natural gas.  The current generation of polymer electrolyte membrane (PEM) electrolyzers for ‘splitting’ water suffer from inefficiency and lack of durability due to poor interface between membranes and catalysts.  Quantum computing can simulate different energy states to increase efficiency, while identifying more chemically-compatible catalysts and membranes.  One set of researchers was able to analyze hundreds of quadrillions of material designs in a technique called cluster expansion.  Results led the team to an unexplored set of materials comprising antimony, manganese, oxygen, ruthenium and chromium – a synthesis of which exhibited catalyzing activity eight times higher than those currently on the market.[7]  A 100% efficiency rate for producing green hydrogen could production costs by a third.

Industry:  As vital as the war against global warming is, construction cannot grind to a halt overnight.  The world consumes more than 4 billion tons of cement annually, a crucial binding agent in the concrete used to make our houses, factories, roads and hospitals.

Unfortunately, cement production causes around 2.5 billion tons of CO2 per year, or some 8% of the global total.  Currently there are no affordable alternatives to cement.  Quantum computing can negate the expense of costly studies, simulating different combinations of materials to design a durable and non-polluting surrogate product.  Some estimates suggest this could reduce emissions by up to 1 gigaton a year by 2035.

Even armed with all this foresight, quantum computing’s most significant breakthroughs might actually surprise us all.  The technologies it could unlock may simply not yet exist on our conceptual radar.  Quantum mechanics might operate on the scale of the infinitesimally small, but its impacts will be global.

How quantum can be a force for good

Like artificial intelligence, if utilized wisely quantum computing has the potential to encourage positive outcomes for several of the UN’s Sustainable Development Goals.  Initiatives including Zero Hunger, Good Health and Wellbeing, Affordable Clean Energy, Industry, Innovation and Infrastructure, and Sustainable Cities and Communities all stand to benefit from quantum tech.

These are worthy targets, compelling us to find smart solutions to some of the hurdles currently facing quantum computing.

For instance, most quantum computers presently operate within cryogenic refrigerators at -273°C and, because of these extreme cooling requirements, still consume more power than standard computers.[8]  Quantum computers in the pipeline could circumvent the need for qubit cooling altogether.  ORCA Computing’s quantum computing system, for instance, uses single photons for qubits at room temperature, without cryogenic cooling.  Trapped ion quantum computing can likewise run at less extreme temperatures, allowing them to process information using minimal power and generating almost no heat.[9]  One study suggests quantum computers could eventually reduce energy usage by more than 20 orders of magnitude compared to conventional supercomputers.[10]

Other doubts remain.  Will quantum computing deepen the wealth divide between richer and poorer countries?  Will it unduly protect incumbent businesses by making industry entry unaffordable to newcomers?  What about quantum computing’s impacts on a labor market still reeling from the triple-whammy of global recession, COVID-19 and AI?  And will modern encryption standards be rendered useless by quantum’s awesome computational power, leaving data and privacy demands in the dust?

Governments must play their part in ensuring quantum computing brings benefits for the many, not just the few.  They must help develop and fund higher education research programs, especially targeting financially-risky areas (such as carbon capture) and humanitarian projects (such as disaster prediction) which currently lack support.  Partnership templates already exist; see current collaborations between IBM and the UK government[11], the Netherlands’ public-private partnership Quantum Delta, or the joint quantum science and technology venture launched by the US and UK in 2021[12].

I feel that we are currently in the foothills of our quantum computing ascent, but already we can gaze up and see the peaks awaiting us.  Across the private and public sectors we must maintain open dialogue to ensure that the route we choose to these lofty heights is accessible for all, and that the destination brings mutual reward.  Quantum tech promises profound changes across society, from finance to national security, to telecommunications and engineering.  By the time we reach a state of ‘quantum advantage’ – performance superiority over conventional computers – perhaps quantum computing could even stay, or help reverse, our most existential threat of all – climate change.

Optimization, simulation and quantum-enhanced machine learning.  Three simple concepts unlocked by the revolutionary power of quantum computing.  They might not save the world, but without doubt they will change it forever.