Frank McGovern: Our island nation is not safe from the threat - we must act
As an island nation with major coastal cities and assets, Ireland is vulnerable to the short, medium and longer-term effects of climate change. Effective global actions to address the causes of climate change are therefore in the country's interest.
We already know that the average global temperature increase in 2015 will break all previous records. The World Meteorological Office (WMO) suggested it will reach the symbolic and significant milestone of 1C, half-way to the 2C adopted by world governments as an upper limit.
The science of climate change is robust. It is well known how changes to our atmosphere impact on our climate. The problem is really around carbon dioxide. In the 1850s, Co Carlow-born scientist John Tyndall answered one of the key scientific questions of the time: why is the Earth so warm?
He built a remarkable instrument that allowed him to identify how water vapour, carbon dioxide and other gases, now known as greenhouse gases, regulate the Earth's temperature.
Measurements started by Charles Keeling in 1958 show the inexorable build-up of carbon dioxide in the atmosphere, raising scientific concerns about what this would do to the Earth's climate.
This year the WMO announced that we are on the verge of breaking the 400ppm (particles per million) level of carbon dioxide in the atmosphere - this has not occurred in the last 800,000 years. It is one of the many observed changes that the United Nations Intergovernmental Panel on Climate Change (IPCC) says are unprecedented over centuries and millennia.
Climate change is all about energy. As John Tyndall showed, carbon dioxide traps energy and keeps us warm, and as carbon dioxide accumulates in the atmosphere, more energy is trapped.
About 90pc of this energy is absorbed by our oceans, along with 30pc of all carbon dioxide.
This causes two major problems - sea-level rise and ocean acidification.
This and other effects of climate change are evident around the world.
The projections are grim. Oceans will continue to warm, sea-level rise will continue during this century, sea ice and glacier volume will further decrease.
Ireland is vulnerable. We have considerable coastal assets, including major cities. Cities such as Cork are vulnerable and this will increase unless adaptation measures are taken.
Extreme events including intense rainfall are expected to increase, resulting in flooding, loss of land and damage to infrastructure.
Actions to address the causes of climate change must be both local and global. The 21st Conference Of Parties (COP) takes place in Paris this week.
The challenges and the risks are now greater than ever.
The IPCC has shown that for a "good chance" (66pc) of staying below a 2C increase, global greenhouse gas emissions need to fall by between 40pc and 70pc relative to 2010 levels by 2050, and reach near or below zero by 2100. As carbon dioxide can stay in the atmosphere for centuries, emissions of this gas need to be reduced to net zero between 2055 and 2070.
Unmitigated climate change would create increasing risks to economic growth and society. Delaying actions only increases costs. The benefits are not only a stable climate but improved human health, energy and food security and environmental quality.
Ahead of the Paris COP, the good news is that 177 countries, representing over 95pc of global emissions, have stated that they will take action.
The bad news is that these commitments do not add up to a below-2C world, and much more is needed from everybody.
A Paris agreement will create the momentum, and a mechanism, to increase global ambition to do what is needed.
Doing this will make us wealthier, healthier and, if it does not make us happier, at least it will give us the ability to live in a sustainable world.
Frank McGovern is head of climate change research at the EPA