One of the five strategic objectives of the International Civil Aviation Organisation (ICAO) is environmental protection.

ICAO’s key environmental goal is to achieve net-zero carbon emissions by the year 2050 in support of the Paris Climate Accords.

As of February, 195 members of the United Nations Framework Convention on Climate Change are parties to the agreement.

Net-zero emission is defined as the reduction of greenhouse gas emissions as close as possible to zero. Any remaining emissions are re-absorbed from the atmosphere by oceans and forests.

Net zero is reached when all the carbon emissions have been eliminated as far as possible and the remaining emissions are eliminated through other mitigation methods such as tree planting and other natural forms of CO2 absorption.

The Paris Agreement's long-term temperature goal is to keep the rise in mean global temperature to well below 2.0 °C above pre-industrial levels, and preferably limit the increase to 1.5 °C recognising that this would substantially reduce the effects of climate change. Emissions should be reduced as soon as possible and reach net zero by the middle of the 21st century.

To stay below 1.5 °C of global warming, emissions need to be cut by roughly 50 per cent by 2030.

Recently, TT has been experiencing the effects of climate change by the record-breaking outside air temperatures.

According to the European Commission, the aviation sector creates 13.9 per cent of the emissions from transport, making it the second biggest source of transport emissions after road transport.

If global aviation were a country, it would rank in the top ten emitters. Someone flying from Lisbon to New York and back generates roughly the same level of emissions as the average person in the EU does by heating their home for a whole year.

ICAO’s 2022 Environmental Report, Innovation for a Green Transition, identifies renewable hydrogen as an alternative fuel that can achieve almost net-zero emissions.

The by-product of hydrogen as a fuel is water vapour.

Today, most high-altitude rockets are entirely fuelled with liquid hydrogen and liquid oxygen cryogenic propellants.

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Liquid-fuelled rockets have higher specific impulse than solid rockets and are capable of being throttled, shut down, and restarted.

Specific impulse is a measure of how efficiently a reaction mass engine such as a rocker or jet engine creates thrust.

There is ongoing research to evaluate hydrogen as a possible aviation fuel in the future.

But, several factors hinder the possible use of hydrogen in commercial flights, such as onboard storage, safety concerns, regulatory requirements, the high cost of producing the fuel and the need for dedicated infrastructure at airports.

In support of the long-term environmental objectives for civil aviation, the two major aircraft manufacturers: Boeing and Airbus are involved in ongoing research to demonstrate the feasibility of hydrogen propulsion systems for fut