Weapons of Mass Destruction (WMDs) continue to pose serious threats to global peace and security. However, understanding the true nature of these weapons, coupled with concerted international efforts, is key to mitigating the risks they present. This article focuses on explaining WMDs, their types, effects, and countermeasures.

Simply put, WMDs are lethal weapons with the potential to cause harm or death to a large number of people and cause extensive damage to man-made structures or natural environments. The impact of WMDs cuts across political, socio-economic, environmental, and security dimensions. They contain nuclear, radiological, biological, and chemical substances, which explains their potential for large-scale destruction and death.

Nuclear weapons, arguably the most potent of the WMD, result in colossal damage through an uncontrolled nuclear reaction. They have seismic, thermal, and radioactive effects that can obliterate cities, as observed in Hiroshima and Nagasaki during World War II. Similarly, radiological weapons enhance conventional explosives with radioactive material, causing contamination over a vast area.

Next are biological weapons, which use pathogens or toxins to disrupt the biological functions of the organism, causing disease or death. The contagion in these weapons could spread and cause an epidemic, making them exceedingly potent. Lastly, chemical weapons contain toxic chemicals, which when released, can cause impairment, irreversible health effects, or death. These substances often have immediate effects but may also cause long-term damage to the environment and human health.

To counter the threats of WMD, it's essential to pursue non-proliferation and disarmament treaties and agreements, such as the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the Chemical Weapons Convention (CWC). These treaties aim to deter the manufacturing, stockpiling, and use of WMDs. They also encourage the peaceful use of nuclear energy.

Furthermore, enhancing and implementing rigorous international inspection and verification systems and mechanisms is pivotal. Such measures should be backed up with sanctions against countries violating the treaties.

Public awareness and education play a crucial role too, in understanding the humanitarian consequences of WMDs. As we advance technologically, it's also vital to guard against non-state actors' access to these weapons, especially in the era of cyber threats and terrorism.

In conclusion, WMDs represent one of the gravest security challenges. While the destructive potential of these weapons renders them threats to mankind, collective international commitment can significantly reduce and possibly eliminate their risks. It's incumbent on all nations to be committed to international non-proliferation and disarmament efforts to ensure the safety of generations to come.