The 5 Questions Everyone Should Be Asking About Climate Change

There are two crucial numbers to understand when it comes to climate change. The first is 51 billion - the number of tons of greenhouse gases that the world adds to the atmosphere each year. The second is zero - the number we must reach to stop global warming and avoid the most severe impacts of climate change.  

Reaching zero means transforming how every country and every sector of society operates. From how we generate electricity, manufacture goods, grow food, and move people and products, to how we heat and cool our buildings, every part of our lives needs to change. Reducing emissions isn’t enough, we need to eliminate them entirely.  

Greenhouse gases trap heat in the atmosphere, warming the planet. Once released, they linger for a long time; about one-fifth of the carbon dioxide emitted today will still be in the atmosphere 10,000 years from now. The more greenhouse gases we emit, the more heat gets trapped, and the more the Earth's temperature rises.  

Before the Industrial Revolution in the mid-18th century, the Earth's carbon cycle was in balance. Natural systems absorbed as much carbon dioxide as was emitted. But that balance changed when we began burning fossil fuels - ancient, carbon-rich materials like coal, oil, and natural gas formed from compressed plant matter over millions of years. Burning these fuels releases carbon that had been stored underground, adding extra CO₂ to the atmosphere.  

Since pre-industrial times, global temperatures have already risen by about 1°C. If current trends continue, we’re on track to see an increase of 1.5°C to 3°C by mid-century, and 4°C to 8°C by the end of the century. These levels of warming could have catastrophic consequences.  

Historically, transitions to new sources of energy have taken decades, even centuries. But we no longer have that much time. To reach zero emissions, we’ll need unprecedented innovation: scientific and engineering breakthroughs, modernized laws and regulations, smarter public policies, and efforts to make green alternatives affordable for everyone.  

Emissions Math: How Much Are We Cutting? 

When talking about greenhouse gas reductions, it's far more effective to frame them in relation to the global challenge: eliminating 51 billion tons of emissions annually. Instead of relying on analogies like “this many tons is equal to taking one car off the road”, which are often vague and misleading, converting reductions into a percentage of the global total provides a clearer sense of scale.  

For example, consider a climate initiative that cuts 17 million tons of greenhouse gas emissions per year. Compared to the global total of 51 billion tons, that amounts to a reduction of just 0.03%.  

At first glance, that might seem insignificant, but it’s not. Every fraction counts, especially if the program has the potential to grow. Small reductions today can become major contributors tomorrow if they can scale efficiently, inspire further innovation, or influence policy and industry standards.  

The Big Five: How Do We Bring Emissions Down? 

Generating electricity accounts for only about a quarter of global greenhouse gas emissions. To reach the goal of net-zero emissions, we must address all human activities that produce emissions - both in how things are made and how they’re used. These sources can be broadly grouped into five key sectors:  

While electricity generation isn’t the largest single contributor, clean electricity plays a critical role in reducing emissions across other sectors. For example, switching to electric cars and buses, electrifying heating and cooling systems, and powering energy-intensive industries with renewable electricity rather than natural gas are all essential steps. Clean electricity isn't the whole solution, but it’s a foundational part of one.  

How Can We Understand Energy Scales in Simple Terms?  

Understanding energy measurements is essential when comparing the power output of various clean energy technologies. The numbers can grow quickly, so using shorthand makes it easier to grasp their scale.  

• A kilowatt (kW) is 1,000 watts. 

• A megawatt (MW) is 1 million watts. 

• A gigawatt (GW) is 1 billion watts.

To put that into context:  

• When you hear kilowatt, think of the energy needs of a single home. 

• A gigawatt is enough to power a city. 

• And 100 gigawatts or more could supply energy for a large country. 

How Much Space Do Different Energy Sources Need? 

Power density is an important factor to consider because different energy sources require vastly different amounts of space to generate diverse amounts of power. Understanding how much land or water area is needed to produce a certain amount of energy helps us plan and evaluate the feasibility of various clean energy technologies. Here are some examples of differences between clean energy power sources:  

How Can We Make Clean Energy Affordable for All? 

The reason we continue to emit large amounts of greenhouse gases is that, if we ignore the long-term environmental costs, current fossil fuel technologies remain the most affordable and widely used solutions. Many zero-carbon alternatives are still more expensive than their fossil fuel counterparts. This cost difference is known as the Green Premium.  

To accelerate the transition to clean energy, we need to reduce these Green Premiums enough so that middle-income countries can afford and choose clean technologies over fossil fuels. Making clean energy economically accessible worldwide is essential for achieving global emissions reduction goals.  

Conclusion

Solving climate change starts with asking the right questions. By understanding emissions, energy use, space requirements, and costs, we can make smarter decisions about our path to zero.  These five key questions aren’t just for conversation—they’re a guide to action. If we focus on clear goals and affordable, scalable solutions, we can make real progress toward a cleaner, more sustainable future.