The world may have signed a pact to tackle climate change last December, but its catastrophic effects are still being felt far and wide.

A drought in Vietnam - the worst to hit the country in nearly a century - is affecting rice farmers badly.

A heat wave in Malaysia has led to school closures there. Scientists predict that rising sea levels, driven by climate change, could upend the lives of more than 13 million Americans by the end of the century.

It is not surprising, then, that when The Straits Times asked readers what climate change means to them in an online poll, about 29 per cent - 133 out of 455 of them - said it meant floods, droughts, famines and other natural disasters.

The poll was part of a four-part climate change series that started on March 4 in ST's Science pages.

The series, which ended last week, highlighted various aspects of climate change - from its effects on coral reefs to measures that cities take to mitigate the effects of prolonged rain or dry spells.

In the poll, respondents could pick more than one answer to the question: What does climate change mean to you?

Besides natural disasters and an open-ended option, the other possible answers were :

•An unpleasant situation (rising temperatures causing discomfort, unpredictable weather resulting in inability to plan activities);

•Biodiversity affected (plants and animals may die out);

•Education and research (opportunity for innovation in terms of renewable energy, efficient technology, environmental awareness)

•Don't know, don't care.

While natural disasters was the top choice, the impact on biodiversity was a close second, with 128 readers (28 per cent) choosing that as the meaning of climate change.

Training administrator April Chong, 38, picked two options - climate change as calamity and affecting biodiversity. Changing global temperatures have led to droughts and floods, which affect agriculture, potentially leading to a food shortage, she said.

Administrative executive Kellie Chew felt that climate change implied an unpleasant situation. Madam Chew, 48, said: "Climate change not only causes physical discomfort, but also affects the mood of everyone around. People are feeling more lethargic and have lower tolerance."

But Mr Wilson Ang, 34, who has led youth delegations from Singapore to a number of climate negotiations since 2007, said climate change is not all doom and gloom.

For the executive director of charity Global Compact Network Singapore, which promotes corporate social responsibility, climate change is an opportunity for education and research. He said: "It could spur innovation in many areas... or even at the individual level. People can fix things and recycle instead of throw them away."