Small numbers of people per household on average use more energy and goods per person. Greater numbers of households require more natural resources for construction. The possible result of this problem may be insufficient natural resources to meet consumer demand without endangering habitats important to biodiversity.

Personal freedom and social choice may come at huge environmental cost. Direct costs include visible damage to animal habitats and plant life. Indirect costs include the release of more greenhouse gases.

The effects of such “personal freedom and social choice” have already surfaced in south-west China’s Wolong Nature Reserve. In Wolong, they found that a reduced average household size was directly tied to an increase in homes, and thus an increase in the amount of firewood consumed for cooking and heating. The rise in wood fuel use has contributed to disappearance of forests and to the loss of habitats for giant pandas.

Curious about whether other parts of the world were experiencing similar phenomena, they got the support of a team of researchers including Stanford’s Paul Ehrlich, well-known for his population studies, to find out the household dynamics in 141 countries between 1985 and 2000. Their study proved that the difficult choice of Wolong is part of a global trend.

In the 76 countries considered biodiversity “hotspots”, such as the United States, Brazil, Australia, and Kenya, the number of households grew by 3.1% every year, while the population increased just 1.8%. Meanwhile, the number of people per home dropped from 4.7 to 4.0. The decline in household size has resulted in 155 million additional households in hotspot countries, almost always limiting biodiversity.

In the 10 non-hotspot countries — those without high-density areas of animal and plant species — similar results were found, though on a lesser scale. Even in countries experiencing population decline, such as New Zealand, the number of households still increased because of a reduction in household size.

An aquarium(水族馆) that has closed because of the COVID-19 outbreak is asking people to make video calls to the aquarium’s eels(鳗鱼).

The reason? Aquarium workers fear the sensitive creatures may not remember humans’ existence, nor remember that humans do not present a threat. The aquarium has been closed since the start of March. Its sea animals have become used to a largely human free environment during the two-month period of calm. But the aquarium said the situation was having some unexpected effects.

“Creatures in the aquarium don’t see humans except keepers and they have started forgetting about humans,” the aquarium said on its Titter this week, “Garden eels in particular disappear into the sand and hide every time the keepers pass by.” That is causing difficulties for keepers trying to check on the health of the animals. So the aquarium decided to offer an invitation to the public. “Could you show your face to our garden eels from your home?” It is describing the new effort as a “face-showing festival”.

Garden eels are very sensitive by nature. But the 300 garden eels that live in a tank at the aquarium had become used to humans. They rarely hid in the sand from visitors. To try to reintroduce the eels to humans, the aquarium is putting five computers in front of their tank. The public can connect through the Face Time app.

Once the video calls start, people are supposed to show their faces, wave their hands and talk to the eels. But considering the quiet nature of the animals, callers are asked not to shout.

The “face-showing festival” is set to take place Sunday through Tuesday, during Golden Week holiday. It has gotten plenty of support. One Twitter user wrote, “Interesting! When you gaze at the garden eels, they gaze at you. I’m happy to take part.”

Extreme heat can kill people, even though most of the deaths are preventable. It is reported that in the 24 years between 1979 and 2003 more people died in the United States of extreme heat than from hurricanes, lightning, tornadoes, floods and earthquakes. 【小题1】 The golden rules are to drink plenty of water, dress in cool clothes and stay in the shade if possible.

【小题2】 Often after many months without rain, a single spark is all that is necessary to create a big fire. Wildfires can move at great speed and will destroy everything in their path. They can quickly change direction, which makes it very difficult for someone on the ground to escape. 【小题3】 In 2010 such fires in Russia killed 62 people and destroyed about 23, 000 square kilometers. A recent UN report suggests that the growing number of wildfires around the world may be contributing to global warming. 【小题4】 Climate change causes drought (干旱); drought causes wildfires; and wildfires cause further climate change.

【小题5】 This is probably due to a natural process, but it is reasonable to assume that this process is being speeded up by mankind’s release into the atmosphere of large amounts of greenhouse gas.