Negative Emission Technologies (NETs) have become a popular topic in the fight against climate change. These technologies remove carbon dioxide (CO2) from the atmosphere and store it in ways that reduce the overall amount of greenhouse gases in the atmosphere. NETs, therefore, have a significant role to play in meeting the targets set by the Paris Agreement.

The Paris Agreement signed in 2015 aimed to limit the global temperature rise to below 2°C above pre-industrial levels, with an ambition to limit warming to 1.5°C. Achieving this goal requires massive reductions in greenhouse gas emissions, including CO2, which is the most significant contributor to global warming. Scientists agree that reducing emissions alone will not be enough to meet the Paris Agreement targets. This is where NETs come in.

There are several types of NETs that have been developed and tested. These include:

1. Afforestation and reforestation: Planting and regrowth of forests, which absorb CO2 from the atmosphere.

2. Biochar: The burning of organic matter under low-oxygen conditions to create charcoal, which can be buried in soil to store CO2.

3. Direct air capture: The removal of CO2 from the air using chemical processes and then stored underground.

4. Ocean fertilization: The addition of nutrients to the ocean to increase phytoplankton growth, which absorbs CO2 from the atmosphere.

5. BECCS (Bioenergy with Carbon Capture and Storage): The use of plants to generate energy and capture the CO2 released, which is stored underground.

NETs are still in their infancy, and only a few are currently operational. However, they have the potential to remove billions of tonnes of CO2 from the atmosphere each year. A study by the Intergovernmental Panel on Climate Change (IPCC) estimates that NETs could remove 100-1000 gigatonnes of CO2 from the atmosphere by 2100. This would enable us to meet the Paris Agreement targets.

The Paris Agreement recognizes the importance of NETs and encourages their use. However, it is essential to note that NETs should not be considered as a silver bullet solution to climate change. Their use should not be used as an excuse to delay reducing emissions, which remains the most effective way to address climate change.

Moreover, the use of NETs also has its challenges, including high costs, land-use constraints, technical uncertainties, and potential negative environmental impacts. Therefore, careful consideration of the potential risks and benefits of each type of NET is necessary.

In conclusion, Negative Emission Technologies have an essential role in meeting the Paris Agreement targets. They present an opportunity to remove CO2 from the atmosphere and store it in ways that reduce the overall amount of greenhouse gases in the atmosphere. However, careful consideration of the potential risks and benefits of each technology is necessary. In addition, NETs should not be seen as a substitute for reducing emissions, which remain the most effective way to address climate change.