The U.N. Climate Change Conference, held recently in Nairobi, Kenya, renewed the world's attention to what is commonly known as global warming, which most scientists say is caused by carbon dioxide and other greenhouse gas emissions largely coming from rich countries. But experts say deforestation in developing countries such as those in Africa also exacerbates the effects of climate change. The Lake Naivasha area of Kenya is experiencing many of the effects of climate change, as Cathy Majtenyi reports.
Giraffes, wildebeest, and other animals graze lazily on a plain in Kenya's Rift Valley, about an hour north-west of the capital Nairobi.
There was a time when the light green plain in the distance was under water, as an inlet of Lake Naivasha - one of several lakes in the Rift Valley.
Sarah Higgins, a farmer and environmentalist with the Lake Naivasha Riparian Association, says she has seen many changes in her farm's landscape since moving here 36 years ago.
"We have seen the area that we work in drying up - definitely," she said. "We used to guarantee our rain every year, so we could guarantee our crop. But now this is not happening; now we are drying up."
Lake Naivasha normally has cycles of rising and falling water levels, but Higgins says she and other farmers in the area have observed that these cycles have been disrupted.
The water that fills Lake Naivasha comes from rivers and streams originating from the Abederes mountain range that forms the eastern wall of the Rift Valley.
The Aberdares used to be covered by thick forests that trapped moisture, kept temperatures cool, and performed other functions including supplying plentiful rainfall to the area.
But massive deforestation has taken place in the Aberdares range and other wooded areas in Kenya over the past few decades.
The deforestation has come about from people clearing the land for farms, timber merchants over-logging, government selling or giving away large tracts of forest in corrupt deals, and other forms of mismanagement.
This has caused many of the rivers and streams feeding Lake Naivasha and other lakes to shrink or dry up, leading to a drop in water levels.
There is also less rain in the area, in part because there is less forest cover to trap moisture and attract cloud cover.
John Njoroge, a farmer and conservationist in the Aberdares area, points out grassy plains in the nearby hills that once were forested, but have since been burned and cleared by the local community.
Njoroge says he has noticed less rain and changing rainfall patterns.
"We have just now witnessed a change for about one-and-a-half years near Kinangop [forest] without rain," he said. "And some years back, it was just raining about three times a year. We are just expecting [rains] now in March and October, but now we are just getting one season rain around in December, which is just raining accidentally."
Deforestation is one of several human activities that experts say contribute to climate change.
They are especially worried that the emissions of carbon dioxide, methane, and other gases into the air are forming a barrier that prevents the sun's energy from radiating back into space, thus raising the earth's temperature.
These scientists blame climate change for causing more intense and frequent droughts, floods, hurricanes, rising sea levels, and other negative effects in different parts of the world.
In a poor country like Kenya, the cheapest and most efficient way to mitigate the harmful effects of climate change is to have lots of trees. Trees absorb excess carbon dioxide and other harmful gases from the atmosphere. But when trees are cut down, this process is halted.
The effects of deforestation and changes to the atmosphere, in turn, have caused hardship for the local population.
Kenya Wildlife Service scientist James Mathenge describes what he has witnessed in the Aberdares and another water catchment area called the Mau forest.
"The effects of climate change that I have seen in this area is that there is, one, loss of species, that is both plants and animals due to drought, it's prolonged drought, and these ones, they are really causing this ecosystem to lose a lot of biodiversity in terms of big mammals and small mammals and also in terms of the plants," said Mathenge.
Experts agree that planting trees is the best way to restore forest cover in Kenya and other parts of Africa. Trees, in turn, are expected to mitigate some of the local effects of climate change.
Kenyan Environment Minister Kivutha Kibwana admits that deforestation is a huge problem in his country - but says a new forestry law has just been enacted.
"We are in the process of really reversing previous policy so that people know that you can't destroy forests and get away with it," said Kibwana. "The government will not dish out forest land to you."
In the meantime, people like conservationist John Njoroge are planting seedlings and doing what they can to tackle the menace of climate change, one tree at a time.