Not so. Take subsidies paid to the fishing industry: "...governments subsidize the destruction of oceanic resources to the tune of $15-30 billion each year. In 2001, subsidies paid to the fishing industry in Japan reached $2.5 billion, equal in value to a quarter of the catch. U.S. fishing subsidies totaled $1.2 billion, exceeding the worth of 30 percent of the U.S. catch.... A global network of marine reserves protecting up to 30 percent of the world's oceans would cost around $13 billion - far less than the subsidies that currently promote overfishing. Such a network would also create some 1 million new jobs and bolster the number of fish that can be caught in nearby waters." (reference, emphases mine)
Also consider ecosystem services - the economic benefits provided by a healthy environment, like flood control, water filtration, and CO2 absorption. A 1997 paper in Nature (see also here) concluded "For the entire biosphere, the value (most of which is outside the market) is estimated to be in the range of US$16-54 trillion (1012) per year, with an average of US$33 trillion per year. Because of the nature of the uncertainties, this must be considered a minimum estimate." An estimate of the value of Canada's boreal forests put the value of their ecosystem services at $93 billion a year, 9% of Canada's GDP.
Then there is the Stern report, which stated that it would be far cheaper to spend money to prevent global warming now, rather than trying to deal with its effects later.
Environmentalists just want more government restrictions on freedom.
Your freedom to drink clean water and breathe clean air, or the freedom of multinational corporations to pollute? Whose rights will be affected if, say, the oceans run out of fish?
There is more forest in the USA now than there was 100 years ago!
This is true. But is it healthy forest?
There is more forest now because most of the continent was deforested in the 19th century. Before European settlers arrived, there were more than a billion acres of forest in the US (including Alaska). Now there are about 750 million acres, young, fragmented, and radically changed from the pre - European condition: 10% of the 800 tree species in the USA are non native species.
The latest data ("Forest Resources of the United States, 2002") says that about 56 million acres of that are tree plantations - not natural forests but large stands of particular trees that offer a profit but poor habitat. Another 504 million acres are classified as timberland - land that could produce timber - and is occasionally logged for that purpose. In addition, forests are fragmented by roads and urban and suburban sprawl. This is one reason for the rapid decline in the population of the Cerulean Warbler and other species which require large tracts of undisturbed forest.
As economy and population booms, these pressures will increase. "In the last decade, the South lost 2.9 million acres to sprawl while another 4.5 million acres of native forest were replaced with fast growing pine plantations. In addition, logging is predicted to increase across the South by 50% by the year 2040 with a loss of as much as 31 million acres of forested land." (reference)
The National Atlas website has a fascinating tool that lets you look at forest fragmentation in the USA, as well as a lot of other data. I also highly recommend The Hidden Forest by John Luoma as an overview of forest ecology.
Polar bear populations are actually growing, so melting ice from global warming isn't a threat.
Polar bear populations are increasing. This is mainly due to a global ban on hunting in the 1970's. Since that time polar bear population has increased from 5,000 worldwide to 20,000 or so.
But the polar bears are showing considerable signs of stress. "Polar bears in western Hudson Bay weigh about 15 percent less (about 150 pounds less for an adult male) than they did 30 years ago." (reference) The Hudson Bay bear population is dropping, with documented decline in reproductive rates and survival of offspring.
And it's not just in Hudson Bay: Polar bears in Alaska are drowning, probably because the melting ice means they have to swim longer distances. (reference) Polar bears are also endangered by pollution, especially around Norway and Russia. (reference)
Environmentalists killed millions by banning DDT!
Tim Lambert, on his blog Deltoid and his older blog has a ton of information regarding what really happened with DDT and malaria in the third world. There was never a global ban on DDT. The United States banned DDT after we had eradicated malaria.
In third world countries, insects quickly developed resistance to DDT from overspraying (see also here) and malaria cases surged in the late 60's and early 70's. Since then, other methods have been developed. DDT is still recommended by the WHO for use in residual indoor spraying, in which a small amount of DDT is sprayed on interior walls to discourage mosquitoes from resting indoors.
Evolution will take care of everything. The fittest species will survive, others will die out.
Evolution will indeed kick in. Insects and microorganisms (many of which just happen to cause disease) will evolve very quickly, because they reproduce frequently and in great quantities. A look at the rapid development of pesticide resistance in insects demonstrates this. Larger vertebrates, who require several years to reach sexual maturity and who produce smaller broods, will not be so lucky.
We are going in the right direction already.
After all, air and water is cleaner in the United States that it was 30 years ago, right? The question is, have we gone far enough, and are we moving fast enough? Our progress is reason for hope, but it's not a reason to dismiss the serious problems we still face.
Humans are more important than some moss or caterpillars.
This assumes that humans are fundamentally separate from nature. Environmental changes affect humans. Think of natural disasters, or disease spread by insects. What about health problems caused by pollution? What about the fact that 1 billion humans depend on fish to provide their daily protein?
Technology will solve our problems.
This is only partly true. Technology combined with a focus on solving the problem will solve our problems. Technology has historically allowed us to destroy natural resources much faster, rather than making us more efficient. The most technologically advanced nations in the world also use the most resources per capita. (reference, pdf)