Global Warming – What is it and why is it happening? What can we do about it?

We have all heard about climate change or global warming and the rising challenges for the sustainability of our planet from global warming. There are several pieces of research on global warming to confirm whether it’s part of the natural process or man-made. Science has proved on many occasions that global warming is mostly man-made and therefore we can do a lot to reverse its effect. To understand global warming, we need to first understand the greenhouse effect.


Greenhouse effect

As we know that greenhouse is a house full of windows to allow sunlight in to generate heat and it also has a capability to retain this heat. Greenhouse gases have a similar capability of trapping the heat.
Every day our earth is hit by solar radiations with a countless amount of energy. The earth absorbs some of the solar radiations and the energy contained within, while the remaining are reflected back to the energetic Sun. The energy absorbed by the Earth is crucial for the sustainability of the planet and therefore important for human life otherwise the earth would be too cold to live on. However, the problem occurs when the reflected radiations can’t travel outside the earth atmosphere because of barriers known as greenhouse gases. This extra energy retained within our planet causes a rise in the earth’s average temperature – global warming. As our oceans cover approximately 70% of the earth, they are the ones who retain most of this energy.

what are those barriers and where do they come from?

These barriers are greenhouse gases and some of them also exist naturally on our planet, however, their abundance presence caused by human activities have accelerated the greenhouse gas effect resulting in global warming.


The main greenhouse gases include:


  • Carbon dioxide (CO2)
  • Natural gas – Methane (CH4)
  • Nitrus Oxide (N2O)
  • Hydrofluorocarbons (HFCs)
  • Sulphur hexafluoride (SF6)
  • Perfluorocarbons (PFCs)


Carbon dioxide (CO2) is one of the most important greenhouse gas and it is released in our atmosphere from the combustion of fossil fuels such as natural gas, oil and coal. CO2 has a global warming potential (GWP) of 1 and set as a base reference for other GHGs.


Methane is an important source of energy and it is extracted as natural gas and used for power generation, heating our homes, offices and used for several industrial applications. Methane is also released from wetlands, raising cattle, growing rice crops, etcetera. Methane, as compared to carbon dioxide, traps a lot of heat (it has GWP of 28 – 36 as compared to CO2) and is the second most contributor to global warming as believed by scientists.

HFCs are the refrigerant gases used in our fridges and freezers but also widely used in commercial and industrial environments for cooling and heating such as cold rooms.


Surprisingly, water is also contributing to global warming as water has a tendency to evaporate off our lakes and ponds and form clouds but it also exists in vapour form which blocks the heat from escaping and forms more water vapours due to availability of heat. Water evaporation accelerates with an increase in temperature so warmer environment would result in more evaporation and heat-trapping. There are also other greenhouse gases released from the combustion of fossil fuels contributing to global warming and some of them are toxic in nature.

Our increased use of energy, reliance on digital devices, enhanced food production, fast-moving transport systems and including growth in the worldwide population has increased greenhouse gases and in effect, the global temperature has risen.


Since the pre-industrial period (between 1850 and 1900) global temperature has risen by average 1℃ and is increasing by 0.2℃ ever decade. We nearly saw 2019 as the second warmest year on the record when the average global temperature was recorded 1.15℃ above the pre-industrial average.



Fact Box

Did you know…

– The UK has committed to be a net-zero emissions country by 2050 which means all the sectors including residential have to be decarbonised before or by that time.

– The overall greenhouse gases in the UK for the period 1900 – 2019 were 435.2MtCO2e.

– The residential and business sector contributed approximately 15% and 14.8% of total emissions respectively.


The 1℃ lift might seem small but it has risen sea levels, melted glaciers, intensified rainfalls and affected our crop yields and changing habitat for plants and animals.


What are the safe limits of the rise in temperature?

The researchers initially suggested that maximum 2.0℃ rise in global temperature pre-industrial levels should be safe, however, scientists now argue that keeping below 1.5℃ would be a far safer limit for the world which is even more challenging. The time is running out on us as we are already above 1℃ rise.

What can we do about it?

The simplest answer to stopping global warming is to stop releasing greenhouse gases in the atmosphere i.e. no energy generated from conventional (fossil) fuels. But, this is not practically possible immediately and we need the energy to carry out our day to day activities. Our hospitals, workplaces, transport systems, college and universities, etc. are all reliant on energy that mainly comes from fossil fuels. However, we have the following options to make a difference.


  1. Reduce the use of energy – Behaviour change
  2. Use energy in an efficient way – Energy efficiency
  3. Recover, reuse and recycle – Resource efficiency and Energy recovery
  4. Generate renewable energy – Energy from sustainable and zero-emission sources
  5. Afforestation and other green initiatives


Reducing the use of energy is directly related to our behaviours and the way we carry out our routine activities. A small change in our behaviour can make a great difference and some organisations have achieved as high as up to 70% reduction in energy use via behaviour change.


There has been a tremendous amount of work in the field of energy efficiency and there are much more energy-efficient devices and appliances available than we have ever seen. The improvement in power generation from renewable sources is also making a difference, however, fossil fuels are still the biggest contributor in our energy mix, used for most of our power generation, transport and industrial processes.


The climate change caused by global warming is real. It is somehow a natural process but its acceleration due to human activities is damaging our eco-system. Even if we assume for a moment that climate change is natural, the use of fossil fuels has certainly polluted the air we breathe in and has damaged our towns and cities we live in. Tremendous improvement in air quality from lockdown due to COVID-19 has proved this and has also given us hope towards greener future.

The good news is that energy reduction and decarbonisation measures are proving to be effective and showing some positive results. The UK has seen approximately 38% decline in CO2e emissions since 1990 due to power generation from using natural gas as a fuel and moving away from environmentally unfriendly coal. Enhanced power generation from renewable sources including wind and nuclear, and improved energy efficiency has speeded up the UK’s journey towards decarbonisation of its power generation industry. The carbon intensity of power generation for the UK in the year 2019 was 0.25358kgCO2/kWh (0.2556kgCO2e/kWh) which is approx 43% better as compared to the year 2002 which was 0.44628kgCO2/kWh (0.44914kgCO2e/kWh).

What energy and carbon reduction measure you would adopt to start making a difference?

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