The letter, from AI's Secretary-General Irene Khan, highlighted and addressed four "key arguments" for abolition:
- Whether executions achieve justice for the victims of crimes and their relatives
- The death penalty as a deterrent to crime, and the corresponding fear that abolition will lead to higher rates of criminality
- The "ever present" risk of executing the innocent, and
- Whether societies should show their "revulsion" for heinous crimes by executing the perpetrators.
"The death penalty is most commonly used in the belief that it acts as a deterrent to violent crime and governments therefore find it difficult to abandon a measure they believe protects their citizens," the organisation said.
"Scientific studies have, however, consistently failed to find convincing evidence that the death penalty deters crime more effectively than other punishments."
The open letter noted the Asian region was an exception to the global trend towards abolition and urged South Korea to provide leadership and a positive example on human rights.
"The region contains countries with high rates of executions and no apparent prospect of abolition. Nations such as Japan, China, Singapore and Indonesia appear to be staunch supporters of capital punishment," it said.
"Amnesty International believes that the abolition of the death penalty in South Korea would provide the region with much needed human rights leadership and be a valuable example of a nation progressing towards the full protection of human rights.
"Such a step would encourage further positive developments in the region such as the abolition of the death penalty in Cambodia, Nepal and Timor Leste, and the Philippines’ decision this month to abolish the death penalty after it was re-imposed in 1994."
The human rights organisation concluded: "Executions give society the illusion of control over the threat posed to public safety by serious crimes. In the immediate period around an execution there is a feeling that a blow has somehow been dealt against criminality. However, the reality is that capital punishment serves no useful purpose in the fight against crime."
Read the full text of the open letter here.