The Thames Vulnerability Assessment Report shows that changes in weather patterns will lead to a decline in the number of plants, fish and other animals.
"This report shows that climate change is likely to result in hotter, drier summers and warmer, wetter winters. Perversely, this means we will suffer from having both more water, and less, with greater risk from flooding and drought," said WWF-UK freshwater policy advisor, Dr Tom Le Quesne.
Changes in the climate will mean the lawns and flower beds of the typical English garden and the lush green landscape along parts of the Thames will be become more arid and dusty.
Anglers will catch less fish in their local streams as the flow in the Thames and its tributaries drops dramatically in hot summers.
In London there will be an increase in the risk of tidal flooding due to sea-level rises. This is likely to require more expensive flood defences to prevent a major flooding incident in the capital and the Thames estuary.
Insurance premiums will rise due to the increased threat of flooding and water bills will rise as drought makes supplies scarcer and harder to supply.
The population is estimated to increase by two million people by 2026 and this will put even more pressure on the water systems, particularly in hotter, drier summers as gardens are watered more often and residents shower more.
Sewer flooding will also increase as more intense rainfall combines with London's high population density and antiquated drainage system.
"Population growth will place further pressure on our already stressed water supplies. We now need to take action reduce the amount of water each person wastes, lower leakage and reduce pollution," explained Le Quesne.
The chance of rivers flooding in the Thames basin may be five times higher by the 2080s.
Peak rivers flows are predicted to increase by 20% leading to a significant rise in annual average flood damage. Intense summer rain will also mean that more sediment and pollution will be washed into the river, with less chance of dilution if levels are low.
"Taken separately, all the impacts are harmful but taken together they could ultimately destroy an internationally important river system. Therefore, the government needs to develop policies that can address droughts, floods, pollution and climate change simultaneously, rather than treating each in isolation," said Le Quesne.
WWF is grateful for HSBC's support of the WWF-UK Thames programme through the global HSBC Climate Partnership.
Peter Bull, Head of HSBC in the Community, who have supported the WWF-UK Thames programme, said: "HSBC is delighted through our global HSBC Climate Partnership to support WWF's important work in this area. Increasing awareness and understanding of the issues which will face us all as a result of climate change is a vital objective of our partnership."