Private jets are appealing. They are fast, and they look really good. You know what else they do? They emit.
When airplanes operate, they burn fuel and produce greenhouse gases, especially carbon dioxide, and a lot of it.
It is therefore difficult for observers to refrain from commenting on the extensive usage of private jets by world leaders who arrived at Glasgow in the past few days to reach agreements on how to achieve carbon neutrality.
Heads of states, businessmen, and company officials are all facing backlash for using private jets to attend the COP 26 - a global conference on tackling climate change - and emitting tonnes of CO2 in the process.
One of the many ironies that arise out of this situation is that the actions of COP26's participants directly contradict the most talked-about objective of the conference itself - setting and working towards a net-zero carbon emissions target.
FlightRadar24, a Swedish company that tracks real-time flights reported that 182 non-commercial planes flew into the airports of Scottish cities like Glasgow, Prestwick, and Edinburgh since 27 October, BBC reported.
In Glasgow specifically, Cirium, another company that analyses data regarding aviation and travel, told the BBC that a batch of 76 non-commercial planes, including VIP jets, flew into Glasgow in the four days leading up to the first day of COP 26.
In totality, according to reports from aviation sources, more than 400 private jets transported more than 1,000 VIPs and their respective staff to COP26, including the leaders of countries like India, Canada, France, Germany, and Israel, the Sunday Mail (a Scottish tabloid newspaper) reported.
Some of the notable leaders who are being questioned for their decisions to not use greener means of travel are British Prime Minister Boris Johnson, US President Joe Biden, and founder and executive chairman of Amazon, Jeff Bezos.
Prime Minister Boris Johnson flew to Glasgow from the G20 summit in Rome, to attend the climate conference, The Guardian reported.
While returning to London, he could have taken the train. It takes around four and a half hours, and he would have had another opportunity to enjoy the views of the magnificent landscape.
But he choose to take a a short internal flight, on the same day he had literally said, "When it comes to tackling climate change, words without action, without deeds are absolutely pointless."
President Biden has acted no better, and has been on the receiving end of criticism, first for the size of his convoy and then for his private jet.
Ahead of COP26, he went to meet Pope Francis using an 85-vehicle motorcade, WION reported.
Biden reached Glasgow on his private presidential plane - Air Force One - from Rome after attending G20, and after his meeting with the Pope in Vatican City.
Questions have been raised about the need for transporting the US government's cargo aircraft that has carried helicopters, armoured cars like The Beast (Biden's limousine), and vehicles for Biden's motorcade.
Then there is Jeff Bezos, who despite pledging $2 billion to projects aimed at restoring nature and improving food systems, flew in to Glasgow on his $65 million jet.
Research has shown that emissions per kilometre travelled by airplanes have a more damaging consequence on the environment as compared to other means of transport like trains, BBC reported.
But there also exist variations in the types of flights that are used for travelling due to factors such as plane size, levels of occupancy, and flight efficiency.
Private jets, it has been reported, usually emit much more carbon dioxide per passenger as compared to commercial flights.
That is where world leaders are being questioned on a matter of principle.
The models of jets that are popular in use among world leaders, burn approximately 225 gallons of aviation fuel per hour, and therefore, travelling from Rome to Glasgow (a journey of almost three hours) on a private jet would cost 2,813 litres of jet fuel per flight.
The Department for Business, Energy and Industrial Strategy told the BBC that 2.5kg of CO2 is emitted per litre of burn fuel.
Their calculations estimate that prima facie, each world leader's jet, while flying from Rome to Glasgow, emitted 7.1 tonnes of CO2.
However, private jets also produce non-CO2 emissions that contribute to global warming.
Therefore, in effect, with respect to temperature rise, adding the effect of non-CO2 emissions increases the warming caused by 7.1 tonnes of CO2 emitted per flight to 13.5 tonnes of CO2 emitted.
Taking a commercial flight for the same journey would have reduced each flight's emissions by 25 percent.
"A huge amount of fuel is used during takeoff and landing of a plane, no matter how many people you have on board. So an already polluting mode of transport (commercial aviation) becomes even worse (with private jets)," as conveyed to BBC by Dr Debbie Hopkins of Oxford University.
Three questions that are worth asking the world leaders who met in Glasgow to save the planet from a climate catastrophe. Two of them are about logistics, while one is about principles.
Firstly, in a world that is still dealing with COVID-19, where Zoom has become the new normal means of organising and attending meetings, and the fact that virtual meetings of world leaders have happened before, did COP 26 have to have had in-person?
Secondly, COP 26 was immediately preceded by the G20 summit in Rome, Italy. Did both conferences have to be held in difference cities, causing at least 20 extra private jets to fly from Italy to Scotland, emitting a significant quantity of CO2 in the process?
And finally, are world leaders aware of the quantity of CO2, that is, the carbon footprint, that their private jets are leaving behind on their journey to a climate conference that will determine the future of global warming for years to come?
It's unlikely that they aren't, in which case, climate activists like Greta Thunberg can be forgiven for reducing the efforts of world leaders to save the planet as nothing but 'blah blah blah.'
(With inputs from BBC, The Guardian, WION, and the Sunday Mail)